JPH09148651A - Magnetoresistive effect element and magnetic conversion element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anti-ferromagnetic layer high enough in reliability in a practical use, a magnetoresistive effect element equipped with a magnetic multilayered film which is large in MR change rate, has a linear rise characteristics of an MR change rate when an applied magnetic field is in a small range of -10 to 100e or so, high in magnetic field sensitivity, large in MR gradient in a magnetic field of high frequency, and high in heat- resistant properties, and magnetic conversion element such as a magnetoresistive effect head or the like provided therewith. SOLUTION: A magnetic conversion element comprises a magnetoresistive effect element 3, a conductor film, and electrodes. The conductor film is electrically connected to the magnetoresistive effect element 3 through the intermediary of the electrode, and the magnetoresistive effect element 3 is equipped with a magnetic multilayered film composed of a non-magnetic metal layer 30, a ferromagnetic layer 40 formed on the one surface of the non-magnetic metal layer 30, a soft magnetic layer 20 formed on the other surface of the non-magnetic metal layer 30, and a pinning layer 50 which is formed on the surface of the ferromagnetic layer 40 opposite to the non-magnetic metal layer 30 to pin down the sense of magnetization of the ferromagnetic metal layer 40, wherein the pinning layer 50 is formed of FeOX (1.35<=x<=1.55, in term of atomic ratio).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive element for reading out a magnetic field strength of a magnetic recording medium or the like as a signal, and in particular, a magnetoresistive element capable of reading a small magnetic field change as a large electric resistance change signal. and,
The present invention relates to a magnetic transducer such as a magnetoresistive head using the same.

[0002]

2. Description of the Related Art In recent years, magnetic sensors have been made highly sensitive and magnetic recording has been made highly dense, and accordingly, magnetoresistive effect type magnetic sensors (hereinafter referred to as MR
It is called a sensor. ) Or a magnetoresistive effect type magnetic head (hereinafter referred to as an MR head) is being actively developed. Both the MR sensor and the MR head read the external magnetic field signal by the resistance change of the reading sensor section using a magnetic material. However, in the MR sensor and the MR head, the relative speed with the recording medium does not depend on the reproduction output. From MR
The sensor has a high sensitivity, and the MR head has a feature that a high output can be obtained even when reading a signal of high density magnetic recording.

However, the conventionally used Ni _0.8 Fe
M using _0.2 (permalloy) or magnetic material such as NiCo
In the R sensor, the resistance change rate ΔR / R is at most 1 to 3%
However, the sensitivity is insufficient as a read MR head material for ultra-high density recording of several GBPI (Giga Bit Per Inch) or more.

By the way, an artificial lattice having a structure in which thin films having a thickness on the order of atomic diameter of metal are periodically laminated has attracted attention in recent years because it exhibits characteristics different from those of bulk metal. As one type of such an artificial lattice, there is a magnetic multilayer film in which a ferromagnetic metal thin film and a non-magnetic metal thin film are alternately laminated on a substrate. Films are known. Of these, for the iron-chromium type (Fe / Cr), ultra low temperature (4.2
It is reported that K) shows a magnetoresistance change of more than 40%. However, in this artificial lattice magnetic multilayer film, the external magnetic field (operating magnetic field strength) at which the maximum resistance change occurs is more than 10 kOe.
~ Large at several tens of kOe, and it is not practical as it is. In addition, artificial lattice magnetic multilayer films of Co / Ag and the like have been proposed, but the operating magnetic field strength of these is too large.

Under such circumstances, a new structure called a spin valve has been proposed. In this, two NiFe layers are formed with a non-magnetic layer in between.
The FeMn layer is arranged adjacent to the Fe layer. Here, since the FeMn layer and the adjacent NiFe layer are directly coupled by the exchange coupling force, the direction of the magnetic spin of this NiFe layer is fixed up to the magnetic field strength of several tens to several hundreds Oe. The spin of one NiFe layer can freely change its direction by an external magnetic field. As a result, NiFe
A magnetoresistance change rate (MR change rate) of 2 to 5% is realized in a small magnetic field range, which is about the coercive force of the layer. In addition, the following documents have been published.

A. Physical Review B (Physical
Review B), 43 (1991) 1297 Si / Ta (50) / NiFe (60) / Cu (20)
/ NiFe (45) / FeMn (70) / Ta (50)
It is stated that the MR change rate sharply rises to 5.0% with an applied magnetic field of 10 Oe in [the thickness of each layer (unit: Å) in (), the same below).

B. Journal of Magnetism
And Magnetic Materials (Journal of M
agnetism and Magnetic Materials), 93 (1991) 101 Si / Ta (50) / NiFe (60) / Cu (25)
/ NiFe (40) / FeMn (50) / Cu (50)
States that the MR change rate is 4.1% with an applied magnetic field of 15 Oe.

C. Japanese Journal of Applied Physics
Physics), 32 (1993) L1441 The MR change rate when the structure of the above a is a multilayer structure is described. The multilayer structure here is NiFe (6
0) / Cu (25) / NiFe (40) / FeMn (5
The structure of 0) is laminated with Cu in between.

D. Journal of Applied Physics, 61 (1987) 41
70 FeMn, not as a spin valve, but as an exchange coupling film
It describes the magnitude of unidirectional anisotropy and its stability when αFe ₂ O ₃ , TbCo, etc. are laminated with NiFe.

Further, the following publications have been published.

E. Japanese Unexamined Patent Publication No. 2-61572 (US Pat. No. 4,949,039) describes that a ferromagnetic thin film laminated via a non-magnetic intermediate layer exhibits a large MR effect by forming antiparallel arrangement between the layers. . It also describes a structure in which an antiferromagnetic material is adjacent to one of the ferromagnetic layers.

F. JP-A-5-347013 describes a magnetic recording / reproducing apparatus using a spin valve film. In particular, it discloses that nickel oxide is used as the antiferromagnetic film.

In such a spin valve magnetic multilayer film,
MR compared to Fe / Cr, Co / Cu, Co / Ag, etc.
Although less magnitude of change rate abruptly MR curve in the following of the applied magnetic field number 10Oe has changed, 1~10Gbit / inch ²
It is suitable as an MR head material for higher recording density. However, the contents disclosed in these documents and gazettes only show the basic operation of the spin valve film.

By the way, at present, Ni _0.8 Fe _0.2 (permalloy) is mainly used as an MR head material in actual ultra-high density magnetic recording. This is one in which a change in the signal magnetic field from the magnetic recording medium is converted into a change in electric resistance by the anisotropic magnetoresistive effect. The MR change rate is only 1 to 3%. Further, in this case, the magnetoresistance change has a characteristic symmetrical with respect to the increase and decrease of the magnetic field around the zero magnetic field.

As a means for solving such a characteristic, N
With iFe or the like, a shunt layer having a small specific resistance such as Ti is provided to shift the operating point. In addition to this shunt layer, a soft film bias layer made of a soft magnetic material having a large specific resistance such as CoZrMo, NiFeRh is provided to apply a bias magnetic field. However, the structure having such a bias layer complicates the process, makes it difficult to stabilize the characteristics, and causes an increase in cost.
Further, since the gentle portion of the MR change curve generated as a result of shifting the MR curve is used, the MR slope in the unit magnetic field is as small as about 0.05% / Oe, which causes a decrease in S / N and the like. It is insufficient as an MR head material for recording densities higher than 10 Gbit / inch ² .

Further, the MR head or the like has a complicated laminated structure and requires heat treatment such as baking and curing of the resist material in the steps of patterning, flattening, etc.
Heat resistance of about 300 ° C may be required. However, in the conventional artificial lattice magnetic multilayer film, the characteristics are deteriorated by such heat treatment.

In the conventional spin valve film disclosed in the literature, etc., only the basic structure and basic characteristics of the thin film have been discussed, and an MR head structure for realizing super high density magnetic recording and a suitable structure for the MR head structure are suitable. There was no mention of the magnetic multilayer structure.

Further, in the spin valve film, a large MR effect is realized by pinning two magnetic layers with one adjacent antiferromagnetic layer. Therefore, the role of the antiferromagnetic layer is important, and its reliability is extremely important. However, FeM currently used mainly
In the case of n, the Neel temperature is as low as 120 to 140 ° C., which is not practically sufficient. Further, FeMn is easily corroded, and if it is rusted by moisture in the air, as a result, the property as antiferromagnetism is likely to be lost and spin valve operation may not be exhibited.

Further, in the examples shown in the above-mentioned documents, when those thin films are actually applied as an MR head,
The MR gradient is small in the actual magnetic field detection range, and good and stable reproduction cannot be performed as an MR head. Further, as an excellent MR head material in super high density magnetic recording, an MR change curve up to an applied magnetic field of -10 to 10 Oe is also important. However, in the disclosed examples of these documents, there is no detailed discussion of the MR slope in this range.

Furthermore, the MR head is required to be used under a high frequency magnetic field of 1 MHz or more for high density recording / reproducing. However, in the film thickness structure of various conventional ternary magnetic multilayer films, 10 Oe in a high frequency magnetic field of 1 MHz or more is used.
Slope of magnetoresistance change curve in width (MR slope at high frequency)
Of 0.7% / Oe or more, it is difficult to obtain high high frequency sensitivity.

[0021]

SUMMARY OF THE INVENTION The present invention was devised in such an actual situation, and its purpose is to provide an antiferromagnetic layer exhibiting practically sufficient reliability and to provide a large MR.
A magnetic multilayer that exhibits a high rate of change, a high MR sensitivity in a high frequency magnetic field, and a high heat resistance temperature. It is an object of the present invention to provide a magnetoresistive effect element including a film, and a magnetic conversion element such as a magnetoresistive effect head using the magnetoresistive effect element.

[0022]

In order to solve such a problem, the present invention provides a magnetoresistive effect element, a conductor film, and
A magnetic conversion element including an electrode portion, wherein the conductive film is
The magnetoresistive effect element is electrically connected to the magnetoresistive effect element through the electrode portion, and the magnetoresistive effect element includes a nonmagnetic metal layer, a ferromagnetic layer formed on one surface of the nonmagnetic metal layer, and a nonmagnetic metal layer. A soft magnetic layer formed on the other surface of the layer and a magnetic layer formed on the ferromagnetic layer (the surface opposite to the surface in contact with the nonmagnetic metal layer) for pinning the magnetization direction of the ferromagnetic layer. And a pinned layer, wherein the pinned layer is FeO _x (1.35 ≦ x ≦ 1.55, unit is atomic ratio).
Is composed of.

In a preferred aspect of the present invention, the magnetoresistive effect element has a substrate, and the pinning layer, the ferromagnetic layer, the nonmagnetic metal layer, and the soft magnetic layer are sequentially laminated from the substrate side. Is configured as.

In a preferred aspect of the present invention, the pinning layer has a thickness of 100Å to 3000Å.

In a preferred aspect of the present invention, the pinning layer is formed of αFe ₂ O ₃ (hematite) exhibiting antiferromagnetism.

In a preferred embodiment of the present invention, the pinning layer contains αFe ₂ O ₃ (hematite) which exhibits antiferromagnetism.
It is configured to contain at least 30% by volume and 60% by volume or less.

In a preferred embodiment of the present invention, the pinning layer is made of αFe ₂ O ₃ (hematite) which exhibits antiferromagnetism.
It is configured to be a collection of crystallites of 00Å or less.

In a preferred embodiment of the present invention, the pinning layer exhibits antiferromagnetism and its Neel temperature is 120 ° C.-4.
Configured to be 00 ° C.

In a preferred embodiment of the present invention, the pinning layer is formed by sputtering an iron oxide target by an ion beam sputtering method and irradiating the substrate with an assist beam of a mixed gas of Ar and O _2. Configured to be a membrane.

In a preferred aspect of the present invention, the assist beam has an acceleration voltage of 60 to 150 eV and an ion current of 4 to
15mA, Ar: O2 flow ratio 1: 1 to 9: 1, Ar +
It is configured so that the O ₂ flow rate is in the range of 6 to 20 sccm.

In a preferred aspect of the present invention, the pinning layer is a film formed by sputtering an iron oxide target in a mixed gas atmosphere of Ar and oxygen by a high frequency sputtering method. The gas flow rate is 20 ~ of the total gas flow rate.
The film is formed by adjusting the film thickness in the range of 40%.

In a preferred embodiment of the present invention, the ferromagnetic layer is (Co _z Ni _1-z ) _w Fe _1-w (where, by weight, 0.4 ≦ z ≦ 1.0, 0.5 ≦ w). ≦ 1.0), and the soft magnetic layer is (Ni _x Fe
_1-x ) _y Co _1-y (however, 0.7 ≦ x ≦ 0.
9, 0.1 ≦ y ≦ 0.5).

In a preferred embodiment of the present invention, the ferromagnetic layer is (Co _z Ni _1-z ) _w Fe _1-w (where, by weight, 0.4 ≦ z ≦ 1.0, 0.5 ≦ w). ≦ 1.0), and the soft magnetic layer is made of Co _t M _u M ′ _q.
B _r (provided that the number of atoms is 0.6 ≦ t ≦ 0.95, 0.01
≦ u ≦ 0.2, 0.01 ≦ q ≦ 0.1, 0.05 ≦ r ≦
0.3; M is at least one selected from Fe and Ni, and M ′ is at least one selected from Zr, Si, Mo, and Nb). Is configured as follows.

In a preferred aspect of the present invention, the nonmagnetic metal layer is composed of a material containing at least one selected from Au, Ag, and Cu.

In a preferred aspect of the present invention, the magnetoresistive effect element is configured to exhibit a spin-valve type magnetoresistive change due to the magnetization of the ferromagnetic layer being pinned by the pinning layer.

As a preferred aspect of the present invention, the magnetoresistive effect element is configured so that the gradient of magnetoresistive change in a 6 Oe width in a high frequency magnetic field at 1 MHz is 0.7% / Oe or more.

In a preferred aspect of the present invention, the magnetic conversion element is a magnetoresistive head.

In a preferred aspect of the present invention, both ends of the magnetoresistive effect element are joined so that the entire ends thereof are in contact with the electrode portions.

As a preferred mode of the present invention, a soft magnetic layer for connection is further provided between the electrode portions formed at both ends of the magnetoresistive effect element, and the soft magnetic layer for connection and the magnetoresistive effect are provided. The ends of the elements are configured to be connected in contact with each other.

As a preferred embodiment of the present invention, the soft magnetic layer for connection is provided between the magnetoresistive effect element and the electrode portions formed at both ends of the magnetoresistive effect element, and on the lower surface of the electrode portion. Are also configured to be continuously formed in contact with each other.

In a preferred aspect of the present invention, the magnetic conversion element is constructed so as not to have a bias magnetic field applying mechanism.

According to a preferred aspect of the present invention, the ferromagnetic layer is formed by applying an external magnetic field of 10 to 300 Oe in the in-plane direction of the film in the same direction as the signal magnetic field during film formation. The soft magnetic layer is formed by applying an external magnetic field of 10 to 300 Oe perpendicular to the signal magnetic field direction and in the film in-plane direction during the film formation.

According to a preferred aspect of the present invention, the laminated magnetic conversion element is heat-treated at a temperature of 100 ° C to 300 ° C.

In a preferred embodiment of the present invention, the magnetic conversion element has a pinning layer formed thereon and then at 100 ° C. to 300 ° C.
It is configured to be heat-treated at the temperature of.

The present invention also includes a nonmagnetic metal layer, a ferromagnetic layer formed on one surface of the nonmagnetic metal layer, a soft magnetic layer formed on the other surface of the nonmagnetic metal layer, A magnetic multilayer film having a pinning layer formed on the ferromagnetic layer (the surface opposite to the surface in contact with the nonmagnetic metal layer) for pinning the magnetization direction of the ferromagnetic layer. In the resistance effect element, the pinning layer is made of FeO _x (1.35 ≦ x ≦).
1.55, unit is atomic ratio).

Further, the present invention is a magnetic conversion element including a magnetoresistive effect element, a conductor film, and an electrode portion, wherein the conductor film is electrically connected to the magnetoresistive effect element via the electrode portion. The magnetoresistive effect element has a substrate on which a pinning layer for pinning the magnetization direction of the ferromagnetic layer, a ferromagnetic layer, a nonmagnetic metal layer, and a soft magnetic layer. Are sequentially laminated, and the pinning layer is made of FeO _x.
(1.35 ≦ x ≦ 1.55, unit is atomic ratio),
Between the pinned layer and the ferromagnetic layer, Co or C
made of an alloy containing 80% by weight or more of o, thickness 4 to 30Å
The oxygen blocking layer is intervened.

Further, according to the present invention, a pinning layer for pinning the magnetization direction of the ferromagnetic layer, a ferromagnetic layer, a nonmagnetic metal layer, and a soft magnetic layer are sequentially laminated on the substrate. A magnetoresistive effect element, wherein the pinning layer is FeO _x.
(1.35 ≦ x ≦ 1.55, unit is atomic ratio),
Between the pinned layer and the ferromagnetic layer, Co or C
made of an alloy containing 80% by weight or more of o, thickness 4 to 30Å
The oxygen blocking layer is intervened.

According to the above-mentioned invention relating to the magnetoresistive effect element, the antiferromagnetic layer excellent in corrosion resistance and the use thereof are provided.
A magnetic multilayer film having an MR gradient of 0.8% / Oe or more is obtained. Moreover, the rising characteristics of the MR curve at 0 magnetic field are extremely good. Also, the MR slope at a high frequency of 1MHz shows a high value of 0.7% / Oe or more,
Further, it is possible to obtain a magnetic multilayer film having high heat resistance, which does not cause deterioration of characteristics even when heat-treated at about 250 ° C. According to the invention related to the magnetic conversion element having such a magnetoresistive effect element (for example, an MR head or the like), it is possible to obtain an output voltage which is about five times as large as that of a conventional material.
Therefore, an extremely excellent effect of being able to read extremely high-density magnetic recording exceeding 1 Gbit / inch ² with extremely high reliability is exhibited.

[0049]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a specific configuration of the present invention will be described in detail.

FIG. 1 is a sectional view of a magnetoresistive effect element 3 which is an embodiment of the present invention. This magnetoresistive effect element 3 is
The artificial lattice magnetic multilayer film 1 (hereinafter simply referred to as the magnetic multilayer film 1) is provided. In FIG. 1, the magnetic multilayer film 1 is formed on the nonmagnetic metal layer 30, the ferromagnetic layer 40 formed on one surface of the nonmagnetic metal layer 30, and the other surface of the nonmagnetic metal layer 30. The soft magnetic layer 20 and the ferromagnetic layer 40 are located above the ferromagnetic layer 40 in order to pin the magnetization direction of the ferromagnetic layer 40 (which is located below in the drawing, but "above" here means a nonmagnetic metal layer). The layered structure has a pinning layer 50 formed on the surface opposite to the contacting surface).

As shown in FIG. 1, these laminated bodies are usually formed on the substrate 5, and these are laminated from the substrate side to the pinning layer 50, the ferromagnetic layer 40, the nonmagnetic metal layer 30, the soft magnetic layer. The layers 20 are stacked in this order. A protective layer 80 is formed on the soft magnetic layer 20 as shown in the figure.

In the present invention, according to the direction of the signal magnetic field applied from the outside, the mutual magnetization of the soft magnetic layer 20 and the ferromagnetic layer 40, which are formed on both sides of the non-magnetic metal layer 30 via the non-magnetic metal layer 30, are adjacent to each other. It is necessary that the orientation be substantially different. The reason is that, according to the principle of the present invention, when the magnetization directions of the soft magnetic layer 20 and the ferromagnetic layer 40 formed via the nonmagnetic metal layer 30 are deviated, conduction electrons are subjected to spin-dependent scattering. ,
When the resistance increases and the magnetization directions are opposite to each other,
This is because it has the maximum resistance. That is, in the present invention, as shown in FIG. 2, when the external signal magnetic field is positive (upward from the recording surface 93 of the recording medium 90 (represented by reference numeral 92)), the adjacent magnetic layers Components in which the directions of magnetization are opposite to each other are generated, and the resistance increases.

Here, in the (spin valve) magnetic multilayer film used in the magnetoresistive effect element of the present invention, the external signal magnetic field from the magnetic recording medium, the soft magnetic layer 20, and the ferromagnetic layer 4 are used.
The relationship between the directions of the 0 magnetization and the change in the electrical resistance will be described.

Now, in order to facilitate understanding of the present invention, as shown in FIG. 1, there is a pair of soft magnetic layer 20 and ferromagnetic layer 40 with one nonmagnetic metal layer 30 interposed therebetween. The case of a simple magnetic multilayer film will be described with reference to FIG.

As shown in FIG. 2, the magnetization of the ferromagnetic layer 40 is pinned downward toward the medium surface by the method described later (reference numeral 41). Since the other soft magnetic layer 20 is formed via the non-magnetic metal layer 30, its magnetization direction is changed by a signal magnetic field from the outside (reference numeral 21). At this time, the relative angle of the magnetization between the soft magnetic layer 20 and the ferromagnetic layer 40 greatly changes depending on the direction of the signal magnetic field from the magnetic recording medium 90. As a result, the degree of scattering of the conduction electrons flowing in the magnetic layer changes, and the electrical resistance greatly changes.

As a result, a large MR whose mechanism is essentially different from the anisotropic magnetoresistive effect of the usual permalloy.
(Magneto-Resistance) effect is obtained.

The magnetization directions of the soft magnetic layer 20, the ferromagnetic layer 40, and the pinning layer 50 exhibiting the pinning effect change relative to the external magnetic field. The change in the direction of those magnetizations is shown in FIG. 3 corresponding to the magnetization curve and the MR curve. Here, the magnetization of the ferromagnetic layer 40 is fixed in the minus direction (downward from the recording surface of the recording medium 90) by the pinning layer 50. When the external signal magnetic field is negative, the magnetization of the soft magnetic layer 20 also faces the negative direction. Now, for the sake of simplicity, the coercive force of the soft magnetic layer 20 and the ferromagnetic layer 40 is set to a value close to zero. In the region (I) where the signal magnetic field H is H <0, the magnetization directions of both the soft magnetic layer 20 and the ferromagnetic layer 40 are still in one direction.

When the external magnetic field is increased and H exceeds the coercive force of the soft magnetic layer 20, the magnetization direction of the soft magnetic layer rotates in the direction of the signal magnetic field, and the magnetization directions of the soft magnetic layer 20 and the ferromagnetic layer 40 respectively. The magnetization and the electric resistance increase as are antiparallel. Then, it becomes a constant value (state of area (II)).
At this time, a certain pinning magnetic field Hex is generated by the pinning layer 50.
Is working. When the signal magnetic field exceeds Hex, the magnetization of the ferromagnetic layer 40 also rotates in the direction of the signal magnetic field, and the magnetization directions of the soft magnetic layer 20 and the ferromagnetic layer 40 in the region (III) are aligned in one direction. . At this time, the magnetization becomes a certain value and the MR curve becomes 0.

On the contrary, when the signal magnetic field H decreases, the regions (III) to (II) and (I) are sequentially changed in accordance with the magnetization reversal of the soft magnetic layer 20 and the ferromagnetic layer 40 as before. To do.
Here, in the first part of the region (II), the conduction electrons undergo the spin-dependent scattering, and the resistance increases. Area (II)
Among them, the ferromagnetic layer 40 is pinned, so that the magnetization is hardly inverted. However, since the soft magnetic layer 20 linearly increases its magnetization, it corresponds to the magnetization change of the soft magnetic layer 20 and depends on the spin. The proportion of conduction electrons that undergo the scattered scattering gradually increases. That is, for example, Hc is applied to the soft magnetic layer 20.
Ni _0.8 Fe _0.2 with a small anisotropic magnetic field H
By adding k, several Oe to several tens below Hk
With a small external magnetic field in the range of Oe, a magnetic multilayer film having a linear resistance change and a large resistance change rate can be obtained.

In the present invention, the film thickness of each thin film layer has its own constraint value. The thickness of the nonmagnetic metal layer is 15 to
A range of 40Å is good. If the thickness of the non-magnetic metal layer is greater than 40 °, the proportion of conduction electrons flowing only in this layer increases, and the overall MR change is reduced, which is not convenient. On the other hand, if the thickness is smaller than 15 °, ferromagnetic coupling between the soft magnetic layer 20 and the ferromagnetic layer 40 becomes strong, and the anti-parallel spin state for realizing a large MR effect is obtained. Will not be obtained.
On the other hand, the conduction electrons are scattered at the interface between the non-magnetic metal layer and the soft magnetic layer 20 and the ferromagnetic layer 40.
Even if the thicknesses of the two magnetic layers 20, 40 are thicker than 200Å, the substantial effect is not improved. Rather, the overall film thickness is increased, which is not convenient. The lower limit of the thickness of the two magnetic layers 20 and 40 is preferably 16Å or more. If it is thinner than this, heat resistance and processing resistance will deteriorate.

The respective components of the magnetoresistive effect element 3 described above will be described in detail below. The first feature of this magnetoresistive element is the composition of the pinning layer.

The pinning layer 50 of the magnetoresistive effect element according to the present invention is used for pinning the magnetization of the substantially adjacent ferromagnetic layer 40, and the pinning layer 50 is preferably, in particular, FeO _x (1.35 ≦ x ≦ 1.55,
The unit is formed by atomic ratio).

Generally, the chemical composition formula, the α phase of Fe ₂ O ₃ is known as hematite. This material exhibits antiferromagnetism and its Neel temperature is 677 ° C., which is much higher than room temperature.
The high Neel temperature means that the pinning effect has high thermal stability, which is advantageous when the magnetoresistive effect element is applied to an MR head or the like. However, the structure of hematite is called a corundum structure, and has a structure in which Fe ions and O ions are arranged in a complicated manner. Although it is easy to generate in bulk such as single crystal, it is difficult to form hematite showing antiferromagnetism as a magnetic thin film because of its complicated structure. There is an example in which the magnetic thin film is formed with a thickness of 5000 Å or more, but this is within the technical scope of the present invention.
It is extremely difficult to use a thin film with a thickness of 00 to 3000Å. This is because when an oxide film of Fe is to be produced by a thin film forming method in vacuum, O is dissociated in vacuum and Fe ₃
This is because it becomes O ₄ (magnetite).

In view of this point, the inventors of the present invention have made extensive studies and found that if the hematite phase itself is realized, the Neel temperature is too high, which may cause inconvenience in the ordinary MR head manufacturing process. It was Therefore, as a result of thoroughly studying the iron oxide thin film and its degree of oxidation, in FeO _x ,
By adjusting the degree of oxidation within the range of 1.35 ≦ x ≦ 1.55 (unit is atomic ratio), preferably 1.40 ≦ x ≦ 1.55, it is possible to obtain necessary and sufficient characteristics as an MR head. all right. When the value of x is larger than 1.55, oxygen is excessive and atomic oxygen is taken in between the iron oxide lattices in the thin film as it is, resulting in deterioration of characteristics. On the other hand, when the value of x is smaller than 1.35, the characteristics approach to those of magnetite, antiferromagnetism is lost, and spin valve type characteristics are not exhibited.

The pinned layer 50 has a thickness of 80Å to 30.
00Å, preferably 80Å to 1000Å, more preferably 80Å to 800Å, further preferably 80Å to 400Å
It is better to set the range. 80% iron oxide as the pinning layer
If it becomes thinner than Å, it will not exhibit antiferromagnetism. Conversely, a thick portion does not cause much problem, but if it is too thick, the gap length (length between the shields) as the MR head becomes large, and it is not suitable for ultra-high density magnetic recording. Therefore, it is better to be smaller than 3000Å.

The FeO _x composition of the pinning layer 50 may be αFe ₂ O ₃ (hematite) which exhibits antiferromagnetism particularly when x = 1.5 (unit is atomic ratio). At this time, the Neel temperature described above can be set low by selecting the materials of the ferromagnetic layer 40, the non-magnetic metal layer 30, and the soft magnetic layer 20 to be pinned and designing the layer thicknesses thereof. It can be possible to manufacture it as a head.

Further, this iron oxide pinning layer 50 is used.
May contain at least 30% by volume or more and 60% by volume or less of αFe ₂ O ₃ (hematite) exhibiting antiferromagnetism. Since hematite itself has an extremely high Neel temperature, this phase is 30% by volume or more in the pinning layer.
When the content is less than or equal to volume%, the pinning effect is sufficient for practical use of the MR head. However, if it is less than 30% by volume, the antiferromagnetism as the pinning layer is not sufficient and spin valve type GMR (giant magnetoresistance) is not exhibited. On the other hand, if the hematite phase exceeds 60% by volume, the Neel temperature may become too high, which makes it practically difficult to switch the spin pinning direction of the ferromagnetic layer for spin valve operation as described later. It's not convenient. The remaining proportion may be the magnetite phase or the wustite phase. Further, it may be an alloy or compound with another material.

Further, since hematite itself has an extremely high Neel temperature, the pinning layer 50 has αF exhibiting antiferromagnetism.
e ₂ O ₃ (hematite) 100 Å or less, especially 60 to
Even for a collection of 100Å microcrystals, the pinning effect is sufficient for practical use of the MR head. Note that the size of the microcrystal may be measured by observing an image image with a TEM.

The pinning layer 50 does not need to be clearly identified as hematite, has a crystal lattice close to hematite, and has a Neel temperature of 120 ° C. to 400 ° C.
C., preferably 150.degree. C. to 300.degree. C., more preferably 150.degree. C. to 250.degree. C., as long as it exhibits antiferromagnetism.

The pinning layer 50 as described above is formed by a method such as an ion beam sputtering method, a sputtering method, a reactive vapor deposition method, a molecular beam epitaxy method (MBE) or the like. Although the film forming method is not particularly limited, the oxygen amount in the iron oxide thin film can be accurately controlled in the film forming method by the dual ion beam sputtering method. That is, a pinning layer is formed by sputtering an iron oxide target by an ion beam sputtering method and irradiating an assist beam of a mixed gas of Ar (argon) and O ₂ (oxygen) on a substrate to be adhered. By doing so, a pinning layer having good characteristics can be formed. In the case of the ordinary ion beam sputtering method, since the kinetic energy of the sputtering beam incident on the target is large, oxygen is dissociated and only a magnetite thin film can be formed. Therefore, it is preferable to form a film while irradiating a mixed gas of Ar and O ₂ as an assist beam.

At this time, the assist beam with which the substrate to be deposited is irradiated has an accelerating voltage of 60 to 150 eV, an ion current of 5 to 15 mA, and an Ar: O ₂ flow ratio of 1: 1 to 9: 1.
The Ar + O ₂ flow rate may be in the range of 6 to 20 sccm. When the accelerating voltage of the assist beam exceeds 150 eV, the energy is too large, oxygen is implanted, and on the contrary, the crystal lattice is disturbed, and sufficient antiferromagnetic properties cannot be obtained. On the other hand, when the accelerating voltage is less than 60 eV, oxygen is no longer well arranged in the crystal lattice, which lowers the Neel temperature, which is not convenient. The range of 80 to 120 eV is preferable. Ion current is 15
When it is larger than mA, the number of oxygen ions incident on the substrate is too large, oxygen is implanted, and on the contrary, the crystal lattice is disturbed, so that sufficient antiferromagnetic properties cannot be obtained.
On the other hand, when the ionic current is less than 5 mA, oxygen is not well arranged in the crystal lattice, and the Neel temperature is lowered, which is not convenient. It is preferably in the range of 6 to 12 mA. The ratio of the flow rates of Ar and O ₂ in the assist beam is preferably in the range of Ar: O ₂ = 1: 1 to 4: 1. If the ratio of Ar: O ₂ exceeds 9: 1 and Ar is excessive, the effect of adding O ions to the iron oxide thin film cannot be said to be sufficient. On the contrary, when this ratio is less than 1: 1 and O ₂ becomes excessive, the filament for generating the assist beam is easily broken, and the manufacturing becomes impossible. The total flow rate of Ar + O ₂ in the assist beam may be in the range of 6 to 20 sccm. If the total flow rate exceeds 20 sccm, the number of oxygen ions is too large, oxygen is implanted, and on the contrary, the crystal lattice is disturbed, and sufficient antiferromagnetic properties cannot be obtained. On the other hand, if it is less than 6 sccm, oxygen is no longer well aligned in the crystal lattice by the assist beam and the Neel temperature is lowered, which is not convenient.

The pinning layer 50 is formed in the same manner as the ion beam sputtering method with the assist beam described above.
A preferred embodiment is a method using a high frequency sputtering method (RF sputtering method). When the high frequency sputtering method is used, iron oxide is used as a target and Ar (argon) and O _{2 are used.}
Sputtering is performed in a mixed gas atmosphere of (oxygen). At that time, it is necessary to adjust the oxygen gas flow rate so that the flow rate is in the range of 20 to 40% of the total gas flow rate. When this ratio is less than 20%, the bonding force of oxygen of the formed pinning layer 50 is small, the state of oxygen is unstable, and the heat resistant temperature is lowered. Also,
If this ratio exceeds 40%, the plasma will not come on stably during sputtering. Further, even if the plasma is turned on, the substantial sputtering rate is extremely lowered because the oxygen content in the sputtering atmosphere is large. Therefore, impurities taken in the film to be formed increase, and a good film cannot be obtained. When a hematite oxide film is formed by a high frequency sputtering method in an Ar (argon) gas atmosphere that has been generally used conventionally, the hematite oxide film is exposed to plasma and oxygen in the film is removed. Are dissociated, and the desired good hematite oxide in the present invention cannot be obtained. There is also a problem in the thermal stability of the obtained film itself.

The ferromagnetic layer 40 is made of Fe, Ni, Co,
Mn, Cr, Dy, Er, Nd, Tb, Tm, Ce, G
d, etc., and alloys and compounds containing these elements. Particularly, (Co _z Ni ₁ -z) _w Fe _{1 -w} (where 0.4 ≦ z ≦ 1.0, 0.5 ≦ w ≦ 1.0)
It is preferable to configure the composition represented by the following formula. If the composition is out of these ranges, there is a disadvantage that a large change in electric resistance cannot be obtained.

The thickness of the ferromagnetic layer 40 is 16 to
100 °, more preferably 20 ° to 60 °. If this value is less than 16 °, the characteristics as a magnetic layer will be lost. On the other hand, when this value exceeds 100 °, the pinning force from the pinning layer 50 becomes small, and the effect of pinning the spin of the ferromagnetic layer cannot be sufficiently obtained.

Since such a ferromagnetic layer 40 is in direct contact with the pinning layer 50 as described above, the interlayer interaction directly acts on the both, and the magnetization rotation of the ferromagnetic layer 40 is blocked.
On the other hand, the soft magnetic layer 20 described later can freely rotate its magnetization by a signal magnetic field from the outside.
As a result, a relative angle is created in the magnetizations of both the soft magnetic layer 20 and the ferromagnetic layer 40, and a large MR effect resulting from the difference in the direction of this magnetization is obtained.

By the way, in the present invention, as shown in FIG. 18, the pinning layer 50 and the ferromagnetic layer 40.
It is preferable to further interpose an oxygen blocking layer 45 between the above and. The oxygen blocking layer 45 is made of Co (cobalt) alone or an alloy containing 80 wt% or more of Co, and has a thickness of 4 to 35Å, more preferably 6 to 30Å. When the Co component is less than 80% by weight, the blocking effect against oxygen diffused from the pinning layer 50 side becomes insufficient during the heat treatment process step after the formation of the laminated body, and the pinning effect is lost by the heat treatment, resulting in spin valve characteristics. The inconvenience of not showing is generated. The oxygen blocking effect of the oxygen blocking layer 45 is as follows.
Is most effective when the composition is Co (cobalt) alone, and is an alloy containing 80% by weight or more of Co,
The effect can be maintained to a practically sufficient level.

The necessity of the oxygen blocking layer 45 is that FeO _x (1.3) is used as the pinning layer 50 of the present invention.
5 ≦ x ≦ 1.55 (unit is atomic ratio), which is due to the use of an oxide antiferromagnetic material. That is, in the present invention, since the pinning layer 50 is composed of an oxide antiferromagnetic material, for example, general-purpose NiFe (permalloy) or the like is used as the material of the ferromagnetic material in contact with the pinning layer 50. In this case, it has been found that there are problems in thermal stability and heat resistance. In other words, oxygen in the antiferromagnetic material diffuses into the ferromagnetic material during the heat treatment process,
The phenomenon that the pinning effect of spin is lost occurs.

When the thickness of the oxygen blocking layer 45 is less than 4Å, Co does not form a continuous film and the oxygen blocking effect is not exhibited. If the thickness exceeds 35 Å, the coercive force Hc tends to increase, which is not preferable.

The oxygen blocking layer 45 as described above exhibits ferromagnetism and partially overlaps the preferable composition range of the ferromagnetic layer 40. Therefore, the oxygen blocking layer 45 also has the same function as the ferromagnetic layer 40. Therefore, when the oxygen blocking layer 45 is provided,
In terms of film thickness, the thickness t of the oxygen blocking layer 45
the sum of the _b and the thickness t _f of the ferromagnetic layer 40 (t _b + t _f) in the range of the ferromagnetic layer 40 described above, i.e., 16 to 100
Å, more preferably 20 to 60Å. Alternatively, the oxygen blocking layer 45 and the ferromagnetic layer 40 may be formed as a single layer with the same composition made of Co (cobalt) alone or an alloy containing 80 wt% or more of Co. Further, the side in contact with the pinning layer 50 is made rich in Co, and the Co content is gradually reduced as it moves away from the side of the pinning layer 50 to form a layer having both the functions of the oxygen blocking layer 45 and the ferromagnetic layer 40. Good.

The soft magnetic layer 20 is made of Fe, Ni, Co or the like, or an alloy or compound containing these elements.
When a magnetic layer having a small coercive force Hc is used, the rise of the MR curve becomes steeper, and a preferable result is obtained. Particularly preferably a composition represented by _{(Ni x Fe 1-x)} y Co 1-y ( however, 0.7 ≦ x ≦ 0.9,0.1 ≦ y ≦ 0.5 by weight). Here, when x and y are in this range, Hc becomes small and favorable soft magnetic characteristics are obtained, and as a result, favorable MR characteristics with high magnetic field sensitivity can be obtained. On the other hand, if x and y deviate from this range, Hc becomes large, and the MR characteristic with high magnetic field sensitivity cannot be obtained. Such a composition system has a high Co concentration. In the spin valve film, the soft magnetic layer causes a large MR change rate by sensitively changing its direction with respect to a minute external magnetic field. Therefore, its soft magnetic properties are important. Permalloy is known as a typical soft magnetic material, but Ni that constitutes permalloy is a nonmagnetic metal layer 3.
There is a problem with heat resistance because it easily dissolves into a solid solution with 0. Therefore, in order to solve this, as described above (Ni
_x Fe _1-x ) _y Co _1-y (however, 0.7 ≦ x ≦
0.9, 0.1 ≦ y ≦ 0.5), which has a high Co concentration, is preferably selected.

Further, as the composition of the soft magnetic layer 20,
Co _t M _{u M'q} B _r (where 0.6 ≦ t ≦
0.95, 0.01≤u≤0.2, 0.01≤q≤0.
The composition represented by 1, 0.05 ≦ r ≦ 0.3) also shows excellent characteristics. Here, M is at least one selected from Fe and Ni, and M ′ is Zr and S.
Represents at least one selected from i, Mo, and Nb. When M and M ′ are two or more, the total amount of the two or more should be within the above composition range. Since such a composition has a large content of Co, it has an extremely excellent characteristic that the MR change rate becomes larger than that of the previous composition. In addition, heat resistance is also increased. Further, as its crystal structure, it is a collection of ultrafine crystal grains or an amorphous structure, so that it exhibits better soft magnetic characteristics, and as a result, a large MR gradient can be obtained. As a specific example of these compositions, Co is the main component, and Ni and / or Fe are selected so that the magnetostriction is zero. Z to this
The amorphous composition may be stabilized by adding r, Si, Mo, Nb or the like. If Co is less than 0.6, it becomes difficult to obtain amorphous. Although Co may exceed 0.95, it is convenient to add Fe or Ni in a small amount because the characteristics as a soft magnetic material are improved. The content ratio of M'is
0.01 ≦ q ≦ 0.1, and if q is less than 0.01, the effect due to the addition cannot be obtained. When q exceeds 0.1, the characteristics as a soft magnetic material deteriorate. B
(Boron) is a main element for making it amorphous, and its content ratio is 0.05 ≦ r ≦ 0.3. If r is less than 0.05, the effect due to the addition cannot be obtained. If r exceeds 0.3, the characteristics as a soft magnetic material deteriorate.

The soft magnetic layer 20 may have a laminated structure. In this case, the soft magnetic layer 20 includes a first soft magnetic layer formed of Co or an alloy containing 80 wt% or more of Co from the nonmagnetic layer side, and (Ni _x Fe _1-x ) _y Co _1-y ( However, it is preferable that the laminated body includes the second soft magnetic layer formed by the composition represented by 0.7 ≦ x ≦ 0.9 and 0.1 ≦ y ≦ 0.5 by weight. .

The thickness of such a soft magnetic layer 20 is 20 to 20.
The angle is set to 150 °, preferably 30 to 120 °, and more preferably 50 to 100 °. If this value is less than 20 °, good characteristics as a soft magnetic layer cannot be obtained.
On the other hand, when this value exceeds 150 °, the thickness of the entire multilayer film increases, the resistance of the entire magnetic multilayer film increases, and the MR effect decreases.

Such a soft magnetic layer 20 and the ferromagnetic layer 4
The non-magnetic metal layer 30 interposed between 0 and 0 is preferably a conductive metal in order to efficiently guide electrons. More specifically, at least one selected from Au, Ag, and Cu, or at least one or more of
Examples thereof include alloys containing 0 wt% or more.

The thickness of such a non-magnetic metal layer 30 is 1
It is preferable that the angle is 5 to 40 °. When this value becomes 15 ° or less, the soft magnetic layer 2
0 and the ferromagnetic layer 40 are exchange-coupled, and the soft magnetic layer 2
There is a problem that the spins of 0 and the ferromagnetic layer 40 do not function independently. This value is 40Å
Is exceeded, the upper and lower soft magnetic layers 20 and the ferromagnetic layers 4
0, the proportion of electrons scattered at the interface decreases, and M
There is an inconvenience that the R change rate decreases.

As described above, each of these layers must be laminated at least from the substrate 5 side in the order of the pinning layer 50, the ferromagnetic layer 40, the nonmagnetic metal layer 30, and the soft magnetic layer 20. This stacking order is due to the constraint of the pinned layer 50. That is, by starting stacking from the pinning layer 50 on the substrate 5, the antiferromagnetism of the iron oxide thin film that is the pinning layer 50 can be sufficiently realized. Further, from the viewpoint of realizing a larger MR change rate, a pinning layer, a ferromagnetic layer, a nonmagnetic metal layer, a soft magnetic layer, a nonmagnetic metal layer, a ferromagnetic layer, and a pinning layer are formed on the substrate 5. Further laminated structures are of course possible.

The protective layer 80 is formed for the purpose of preventing the surface of the magnetic multilayer film from being oxidized during the film forming process and improving the wettability with the electrode material formed on the surface and the adhesion strength. , This is Ti, Ta, W, Cr, H
It is formed of a material such as f, Zr, and Zn. The thickness is usually about 30 to 300 °.

The substrate 5 is made of glass, silicon, MgO, Ga.
It is formed of a material such as As, ferrite, altic, CaTiO ₃ . The thickness is usually 0.5-10 mm
Degree.

The material and layer thickness of each layer are defined as described above, and at the time of forming the soft magnetic layer 20, an anisotropic magnetic field Hk is applied by applying an external magnetic field in one direction in the film plane described later. 2 to 20 Oe, more preferably 2 to 16 Oe, especially 2
It is preferable to add 10 to 10 Oe. The magnetic multilayer film thus formed has an MR slope of 0.5% / Oe or more, particularly 0.8% / Oe at the rising portion of the MR change curve.
As described above, normally 0.5 to 1.5% / Oe is obtained. Also, M
The maximum hysteresis width of the R change curve is 8 Oe or less, usually 0 to
It becomes 6 Oe. Furthermore, M in high frequency magnetic field of 1MHz
R slope is 0.7% / Oe or more, more preferably 0.8% /
Oe or more, usually 0.7 to 1.5% / Oe,
When used for MR heads for reading high density recording,
Sufficient performance can be obtained. When the anisotropic magnetic field Hk of the soft magnetic layer is less than 20 Oe, the coercive force is almost the same, and a linear MR change curve centering on the 0 magnetic field cannot be obtained substantially. The characteristics deteriorate. On the other hand, if it is larger than 20 Oe, the MR gradient becomes small, and when this film is applied to an MR head or the like, the output tends to decrease and the resolution decreases. Here, these Hk are obtained by applying a magnetic field of 10 to 300 Oe during film formation as an external magnetic field. If the external magnetic field is less than 10 Oe, it is not enough to induce Hk, and even if it exceeds 300 Oe, the effect does not change, but the coil for generating the magnetic field becomes large, costly and inefficient. is there.

The MR change rate is expressed by the maximum specific resistance ρmax
, When the minimum specific resistance is ρsat, (ρmax −ρsat
) × 100 / ρsat (%). The maximum hysteresis width is the magnetic resistance change curve (MR curve).
Is the maximum value of the hysteresis width calculated by measuring. Furthermore, the MR slope is the maximum value of the differential value at -20 to +20 Oe obtained by measuring the MR curve and obtaining the differential curve. The high frequency MR slope is the MR slope when the MR change rate is measured with an alternating magnetic field having a magnetic field width of 1 MHz 6 Oe.

A magnetic resistance effect element may be formed by repeatedly laminating the above-mentioned magnetic multilayer films 1. The number n of repeated laminations of the magnetic multilayer film is not particularly limited, and may be appropriately selected according to a target magnetoresistance change rate or the like. In order to cope with the recent ultra-high density of magnetic recording, the thinner the total thickness of the magnetic multilayer film is, the better. However, when the thickness is reduced, the MR effect usually decreases at the same time, but the magnetic multilayer film used in the present invention can obtain a multilayer film that can sufficiently withstand practical use even when the number n of times of repeated lamination is one. In addition, as the number of layers increases, the rate of change in resistance also increases. However, productivity deteriorates. Further, if n is too large, the resistance of the entire element becomes too low, which causes practical inconvenience. Is preferably 10 or less.
Note that the long-period structure of the artificial lattice can be confirmed by the appearance of primary and secondary peaks corresponding to the repetition period in a small-angle X-ray diffraction pattern. A preferable range of n is 1 to 5 for application to a magnetic transducer such as an MR head for ultrahigh density magnetic recording.

Further, in order to reduce the number n of repeated laminations as much as possible, the soft magnetic layer is one layer and the pinning layer is two layers. From the substrate side, the pinning layer, the ferromagnetic layer, the nonmagnetic metal layer, A structure including a soft magnetic layer, a nonmagnetic metal layer, a ferromagnetic layer, and a pinning layer is preferable.

The respective layers of the magnetic multilayer film 1 are formed by a method such as an ion beam sputtering method, a sputtering method, a vapor deposition method, a molecular beam epitaxy method (MBE) or the like. As the substrate 5, as described above, glass, silicon, MgO,
GaAs, ferrite, altic, CaTiO3 or the like can be used. During film formation, as described above, when forming the soft magnetic layer 20, 10 to 30 in one direction within the film surface.
It is preferable to apply an external magnetic field of 0 Oe. As a result, Hk can be applied to the soft magnetic layer 20. The external magnetic field is applied only when the soft magnetic layer 20 is formed,
A method may be used in which the magnetic field is applied using a device equipped with an electromagnet or the like that can be easily controlled, and not applied when the pinning layer 50 is formed. Alternatively, a method of constantly applying a constant magnetic field throughout the film formation may be used.

Next, the invention of the magnetoresistive effect element 3 provided with the magnetic multilayer film 1 described in the above-mentioned embodiment was developed, the route through which electrons flow was examined in detail, and the invention of the magnetic conversion element was reached. The magnetic conversion element here includes a magnetoresistive effect element, a conductive film and an electrode portion, and more specifically, a magnetoresistive effect type head (MR head),
It is a broad concept including MR sensors, ferromagnetic memory elements, angle sensors and the like.

Here, a magnetoresistive head (MR head) is taken as an example of the magnetic conversion element.
explain.

As shown in FIG. 4, a magnetoresistive effect head (MR head) 150 has a magnetoresistive effect element 200 as a magnetically sensitive part for sensing a signal magnetic field, and both ends of the magnetoresistive effect element 200. It has the electrode part 100, 100 formed in the part 200a, 200a. And
End 200 of magnetoresistive element 200 as magneto-sensitive part
a, 200a have electrode portions 100, 10
It is preferable that they are connected in a state where they are in contact with zero. Note that the conductor films 120, 120 are provided on the electrode portions 100, 10
It is electrically connected to the magnetoresistive effect element 200 via 0. In the present invention, the conductor film 120 and the electrode portion 100 are divided into a conductor film 120 and an electrode portion 100 for the sake of simplicity in order to make the following description easy to understand. However, the conductor film 120 and the electrode portion 100 are originally integrally formed by a thin film forming method. In many cases, these may be considered as one member.

The magnetoresistive effect element 200 as a magnetically sensitive portion in the MR head has a laminated structure substantially similar to that of the magnetoresistive effect element 3 having the magnetic multilayer film 1 shown in FIG. That is, the magnetoresistance effect element 2
00 is replaced by the magnetoresistive effect element 3 having the magnetic multilayer film shown in FIG. 1, and as a result, the magnetoresistive effect element 20.
0 denotes a non-magnetic metal layer 30, a ferromagnetic layer 40 formed on one surface of the non-magnetic metal layer 30, a soft magnetic layer 20 formed on the other surface of the non-magnetic metal layer 30, Magnetic layer 40
And a pinning layer 50 formed on the ferromagnetic layer 40 (on the side opposite to the surface in contact with the nonmagnetic metal layer 30) to pin the direction of magnetization of the ferromagnetic layer 40.

An important point here is that the magnetoresistive effect element 200 formed as described above exhibits a so-called spin valve type magnetoresistive change. The spin valve type magnetoresistive change includes a nonmagnetic metal layer 30, a ferromagnetic layer 40 formed on one surface of the nonmagnetic metal layer 30, and a soft magnetic layer formed on the other surface of the nonmagnetic metal layer 30. A magnetic layer 20,
A pinned layer 50 formed on the ferromagnetic layer for pinning the direction of magnetization of the ferromagnetic layer 40;
The angle formed by the spin of the ferromagnetic layer 40 pinned to 0 is set to be nearly 90 degrees when viewed from the acute angle direction. In practice, the angle is often 45 to 90 degrees, but is preferably in the range of 60 to 90 degrees. Further, the pinning is caused by the direct exchange interaction between the ferromagnetic layer 40 and the pinning layer 50, particularly in the case of the present invention, the direct exchange interaction between the antiferromagnetic layer and the ferromagnetic layer, so that the magnetoresistive effect curve is obtained. The (MR curve) is characterized by being asymmetrical with respect to the plus and minus external magnetic fields centering around when the external magnetic field is zero.

As shown in FIG. 4, in the magnetoresistive effect type head (MR head) 150, the shield layers 300, 300 are formed so as to sandwich the magnetoresistive effect element 200 and the electrode parts 100, 100 vertically. At the same time, the nonmagnetic insulating layer 400 is formed in the portion between the magnetoresistive effect element 200 and the shield layers 300, 300.

Here, the ferromagnetic layer 40 and the non-magnetic metal layer 30 used in the magnetoresistive effect element 200 as the magnetically sensitive portion,
For the soft magnetic layer 20 and the pinning layer 50, it is desirable to use the same material and thickness as those described in the magnetic multilayer film example.

As a result of detailed examination of the path of the current flowing through the magnetic multilayer film of the magnetoresistive element 200, it has been found that the electrons as the current are biased to a certain portion in the magnetic multilayer film. That is, among the layers forming the magnetic multilayer film, the iron oxide forming the pinning layer 50 is almost close to the insulating layer. Therefore, the electrons flow toward the soft magnetic layer 20 or the nonmagnetic metal layer 30 having a low specific resistance. In an MR head using a conventional spin valve film, after forming a soft magnetic layer as a magnetically sensitive portion, a nonmagnetic metal layer,
It was laminated with a ferromagnetic layer and a pinning layer, and an electrode was formed on the upper surface of the layer. In this case, the electrode is in contact with the pinned layer having an extremely high specific resistance, so that the sense current (MR
It becomes difficult for a constant current necessary for operating the head to flow. Further, the contact resistance is large, and the yield is reduced in the manufacturing process.

Therefore, the stacking order is reversed, the iron oxide pinning layer 50 close to the insulating layer is set closer to the substrate 5, and the electrode portion 100 through which the current flows has the magnetoresistive effect as shown in FIG. The end portions 200a, 2 of the element 200 in the stacking direction
These problems can be solved by adopting a structure in which the entire 00a contacts. That is, the electrons are the soft magnetic layer 20.
And flows mainly in the portion sandwiched between the ferromagnetic layers 40. Then, the soft magnetic layer 20 and the ferromagnetic layer 40 are magnetically scattered depending on the spin directions, and the resistance changes significantly. Therefore, a minute change in the external magnetic field can be detected as a large change in electric resistance.

Further, as described above, at least at the time of forming the soft magnetic layer 20, an anisotropic magnetic field Hk is induced by applying an external magnetic field in one direction in the film surface, thereby further improving the high frequency characteristics. can do. Here, M is added to the magnetic multilayer film.
An external magnetic field is applied in the direction in which a current for causing the R effect is applied, thereby inducing an anisotropic magnetic field. Usually, a magnetic multilayer film is processed into a strip shape and a current flows in the longitudinal direction. Therefore, it is preferable to form a film by applying a magnetic field in the longitudinal direction.
In other words, the film may be formed by applying a magnetic field in the same direction as the direction in which the current flows as the MR head, that is, perpendicular to the signal magnetic field direction and in-plane. Then, in the soft magnetic layer forming the magnetic multilayer film, the longitudinal direction of the strip is the direction of easy magnetization,
The strip short side direction becomes the magnetization difficult direction, and the anisotropic magnetic field Hk is generated. Here, since the signal magnetic field is applied in the short side direction of the strip-shaped magnetic multilayer film, the high-frequency magnetic characteristic of the soft magnetic layer is improved, and the MR characteristic in a large high-frequency region is obtained. The magnitude of the applied magnetic field may be in the range of 10 to 300 Oe. Then, the anisotropic magnetic field Hk induced in the soft magnetic layer 20.
Is 3-20 Oe, more preferably 3-16 Oe, especially 3-1
It should be 2 Oe. When the anisotropic magnetic field Hk is less than 3 Oe, the coercive force of the soft magnetic layer 20 is almost the same, and a linear MR change curve centering on the 0 magnetic field is substantially not obtained, and the characteristics of the MR head are improved. to degrade. On the other hand, if it is larger than 20 Oe, the MR gradient (MR change rate per unit magnetic field) becomes small, and when used as an MR head or the like, the output tends to decrease and the resolution decreases. The film of the present invention exhibits high heat resistance, and the MR slope at the rising portion of the MR change curve is 0.5% / Oe or more, particularly 0.8% / Oe or more,
Usually 0.5-1.5% / Oe is obtained. Further, the maximum hysteresis width of the MR change curve is 8 Oe or less, usually 0 to 6 Oe. Furthermore, the MR slope in a high-frequency magnetic field of 1 MHz can be 0.7% / Oe or more, more preferably 0.8% / Oe or more, usually 0.7 to 1.5% / Oe. Sufficient performance can be obtained as an MR head for reading density recording.

Further, when forming the pinning layer 50, it is preferable to apply a magnetic field in a direction perpendicular to the direction of the applied magnetic field when forming the soft magnetic layer 20. In other words, the direction is in the plane of the magnetic multilayer film and perpendicular to the measured current. The magnitude of the applied magnetic field may be in the range of 10 to 300 Oe. As a result, the magnetization direction of the ferromagnetic layer 40 is reliably fixed in the direction of the applied magnetic field (perpendicular to the measurement current) by the pinning layer 50, and the magnetization of the soft magnetic layer 20 whose direction can be easily changed by the signal magnetic field. The most rational antiparallel state can be created. However, this is not a necessary condition and may be the same direction as the direction of the magnetic field applied when forming the soft magnetic layer when forming the antiferromagnetic layer. At this time, after performing the heat treatment at about 200 ° C. in the process after the formation of the magnetic multilayer film, a magnetic field is applied in the direction of the short side of the strip (perpendicular to the direction of the applied magnetic field when the soft magnetic layer 20 is formed). It is preferable to lower the temperature while applying the voltage.

The magnetization rotation of the soft magnetic layer 20 defines the rising portion of the MR curve. In order to obtain a steeper rise of the MR curve, it is desirable that the soft magnetic layer 20 completely changes the direction of the magnetization by the rotation of the magnetization with respect to the signal magnetic field. However, actually, magnetic domains are generated in the soft magnetic layer 20, and domain wall movement and magnetization rotation occur simultaneously with respect to the signal magnetic field. As a result, Barkhausen noise occurred, and the MR head characteristics became unstable.

Therefore, as a result of earnest studies, the inventors of the present invention have shown that, as shown in FIG. 5, the magnetoresistive element 200, which is a magnetically sensitive portion, and the electrode portion 100 for passing a measurement current, respectively, are respectively provided. It was confirmed that the noise can be improved by interposing the coupling soft magnetic layer 500. Of course, in this case, the connecting soft magnetic layer 500 and the entire end portions 200a and 200a of the magnetoresistive effect element 200 are connected in contact with the connecting soft magnetic layer 500. The connecting soft magnetic layers 500, 500 formed adjacent to the magnetoresistive effect element (magnetic multilayer film) magnetically directly contact the soft magnetic layer forming the magnetic multilayer film. The added coupling soft magnetic layer 500 has an effect of bringing the magnetic domains of the soft magnetic layer in the magnetic multilayer film closer to the single magnetic domain structure and stabilizing the magnetic domain structure. As a result, the soft magnetic layer in the magnetic multilayer film operates in the magnetization rotation mode with respect to the signal magnetic field, and is free from noise.
Good characteristics can be obtained.

In order to bring the magnetic domain of the soft magnetic layer in the magnetic multilayer film closer to a single magnetic domain and stabilize the magnetic domain structure, FIG.
Soft magnetic layers 510 and 510 having a shape as shown in FIG.
Is preferably provided. This soft magnetic layer 510 for connection
Indicates the magnetoresistive effect element 200 and the electrode portion 1 which are magnetically sensitive portions.
No. 00, and is continuously formed on the lower surface 101 of the electrode portion 100. This is because the larger the volume of the coupling soft magnetic layer 510 for stabilizing the magnetic domain structure, the greater the degree of stabilization. Moreover, since the voltage effect does not occur when it is in direct contact with the electrode portion 100, the MR effect of the coupling soft magnetic layer itself for stabilizing the magnetic domain structure does not affect the MR effect of the magnetic multilayer film, which is convenient. . Further, in order to more positively stabilize the magnetic domain of the soft magnetic layer in the magnetic multilayer film, an antiferromagnetic layer is provided between the coupling soft magnetic layer for stabilizing the magnetic domain structure and the electrode portion 100. It may be sandwiched.

A hematite-using spin valve M using hematite as a pinning layer as in the present invention.
It is particularly preferable that the R head has a head structure as shown in FIG. That is, the magnetoresistive effect element 200, which is a magnetically sensitive part, and the electrode part 100 for flowing a measurement current.
As shown, the connecting soft magnetic layer 520 and the antiferromagnetic layer 800 (or the hard magnetic layer 800) are sequentially interposed from the magnetoresistive element 200 side as shown. In addition, one end of the coupling soft magnetic layer 520 and the antiferromagnetic layer 800 (or the hard magnetic layer 800) covers a part of the upper part 200 a (in the direction close to the soft magnetic layer) of the magnetoresistive element 200. The other end side is the lower surface 1 of the electrode portion 100 as shown in the figure.
01 and is formed. Further, the electrode unit 100
The end 102 located on the center side of the head covers a part of the upper part 200 a (in the direction close to the soft magnetic layer) of the magnetoresistive element 200, and the upper end of the coupling soft magnetic layer 520 and the antiferromagnetic layer 800. The portions 520a and 800a are formed so as to cover the respective portions.

With such a structure, a longitudinal bias can be applied very efficiently by the effects of both the coupling soft magnetic layer 520 and the antiferromagnetic layer 800 formed in the magnetoresistive effect element 200. As a result, MR head characteristics in which Barkhausen noise is suppressed can be obtained. Also,
Since the end portion 102 of the electrode portion 100 is formed so as to cover the magnetoresistive effect element 200 as described above,
It is possible to provide an MR head in which the signal magnetic field does not decrease at the end of the element and which can easily form a narrow track width of 1 μm or less.

Generally, in an MR head using permalloy, a shunt layer such as Ti or CoZrMo, Ni is usually used.
A bias magnetic field applying layer made of a soft magnetic material having a large specific resistance such as FeRh is provided adjacent to the magnetically sensitive portion. These are called soft film bias and shunt bias, and they work to shift the permalloy curve and create a linear region around the zero magnetic field. However, these mechanisms are complicated and, in the manufacturing process, are the factors that greatly reduce the manufacturing yield. On the other hand, in the above-described magnetoresistive effect element (magnetic multilayer film) of the present invention, since the MR curve rises from the vicinity of the zero magnetic field, the self-current generated by the current flowing through the magnetoresistive effect element (magnetic multilayer film). The bias can produce a linear region around the zero magnetic field. As a result, since it is not necessary to provide a biasing method having a complicated mechanism, it is possible to improve the manufacturing yield, shorten the manufacturing time, and reduce the cost. Further, since there is no bias mechanism, the thickness of the magnetically sensitive portion becomes thin, so that the shield thickness when used as an MR head becomes small, which is very effective in shortening the wavelength of the signal due to ultra-high density recording.

When manufacturing these MR heads, heat treatment such as baking, annealing, resist curing, etc., is inevitable in the manufacturing process, such as patterning and flattening.

In a magnetoresistive effect element having a magnetic multilayer film generally called an artificial lattice, heat resistance often causes a problem because of the thickness of each layer constituting the magnetoresistive effect element. In the magnetoresistive effect element (magnetic multilayer film) according to the present invention, a magnetic field is applied and an anisotropic magnetic field is applied to the magnetic layer, so that after film formation, heat treatment is performed at 300 ° C. or lower, generally 100 to 300 ° C. for about 1 hour. Can fully cope with. Heat treatment is usually performed in vacuum,
It may be carried out in an inert gas atmosphere, in the air, or the like.
By performing the process in a vacuum (under reduced pressure) of 0 ^-7 Torr or less, a magnetoresistive element (magnetic multilayer film) with extremely small characteristic deterioration can be obtained. Further, MR characteristics are hardly deteriorated even in lapping and polishing in the processing step.

Further, after the iron oxide layer which is the pinning layer 50 is formed, the substrate is taken out from the vacuum film forming apparatus, and thereafter, in the air, in an oxygen atmosphere, or in vacuum, 100 ° C. to 300 ° C.
After performing the heat treatment at the temperature of, the heat treatment to approach the hematite phase, and then returning the substrate to the vacuum film forming apparatus,
A continuous spin valve structure (remaining laminated film structure) may be formed. The sizes of Fe and O ions are quite different, and strain due to stress or the like is likely to occur due to vacuum film formation. By this heat treatment, it is possible to reduce the stress and improve the antiferromagnetic property by improving the regularity of the crystal lattice. The heat treatment is preferably performed in the air after forming the pinning layer, but the effect is great even in vacuum, and at least after the pinning layer is formed, the heat treatment may be performed at a temperature of 100 ° C. to 300 ° C. in any step. .

Since the iron oxide thin film of FeO _x (the material forming the pinning layer) in the present invention is an insulating layer having a high withstand voltage, it can be used as a material forming the so-called gap film of the MR head. .

[0115]

The invention of the magnetoresistive effect element and the invention of a magnetic conversion element (for example, an MR head) using the same will be described in more detail with reference to the following specific embodiments. First, a concrete example of the invention of the magnetoresistive effect element 3 (corresponding to FIG. 1) having the magnetic multilayer film 1 will be shown as Example 1.

Example 1 A glass substrate was used as a substrate, which was placed in an ion beam sputtering apparatus and vacuumed to 2.3 × 10 ⁻⁷ Torr. While cooling the substrate at 14 ° C., the substrate was rotated at 20 rpm to prepare an artificial lattice magnetic multilayer film having the following composition. At this time, while applying a magnetic field in the plane of the substrate and in a direction parallel to the measurement current, about 0.3
Film formation was performed at a film formation rate of Å / sec or less.

After film formation, in a vacuum of 10 ⁻⁵ Torr, applying a magnetic field of 200 Oe in the in-plane direction at right angles to the measurement current, 2
By cooling from 00 ° C., the pinning effect of the ferromagnetic layer was induced. In this way, each sample 1-1 to 1-13 of the magnetoresistive effect element as shown in Table 1 was prepared.

[0118]

[Table 1] In Table 1, for example, Sample 1-1 has a main gun acceleration voltage of 1200 eV and an ion current of 120 m on a substrate.
A, a pinning layer FeO _x having a thickness of 1000 Å was formed under the conditions of A, assist beam acceleration voltage 100 eV, ion current 10 mA, Ar flow rate 4 sccm, and O ₂ flow rate 1 sccm.
On top of this, a ferromagnetic layer of a permalloy composition (NiFe) alloy of 38 Å thickness of Ni 81% -Fe 19%, Cu of 88 Å thickness
Is a magnetic multi-layer film formed by sequentially sputtering the non-magnetic metal layer of. The other samples 1-2 to 1-13 are different only in the film forming conditions of the pinning layer FeO _x (thus, each Fe
The composition of O _x is different), and other than that, the laminated structure is the same as that of the sample 1-1.

For each sample, the acceleration voltage and ion current of the main gun used, the acceleration voltage and ion current of the assist gun used, and Ar and O ₂ applied to the assist gun
Gas flow rate, x (referred to as oxidation degree), which is the ratio of O / Fe forming the pinning layer FeO _x , and unidirectional anisotropy H caused by the pinning layer exhibiting antiferromagnetism.
The values of _ua (shift amount from the zero magnetic field of the hysteresis center in the magnetization curve: uniaxial anisotropy) are shown in Table 1, respectively. Here, the degree of oxidation x can be easily determined by a fluorescent X-ray analysis method. As for _Hua , which is a parameter of the strength of antiferromagnetism, the same film forming conditions and the same layer thickness as those used when manufacturing the MR head are used, and the strength of the thin film of iron oxide (pinning layer FeO _x ) Create a magnetic layer,
The magnetization curve of this product was measured and evaluated by the shift amount of the central magnetic field of the hysteresis. As a result, 1.35 ≦ x
It was found that by adjusting the degree of oxidation x in the range of ≦ 1.55 (unit is atomic ratio), a sufficient and sufficient _Hua for operating the MR head can be obtained.

From the experimental results of changing the assist gas flow rates shown in Samples 1-1 to 1-4 in Table 1, pinning was performed when the assist gun Ar + O ₂ gas flow rate was within the range of 6 to 20 sccm. Layer (Samples 1-2 and 1
-3) only has an oxidation degree x = O / Fe of 1.35
It can be seen that it is within the range of 1.55. The value of the unidirectional anisotropy H _ua At this time, appears to minimum required 40O
It is a large value of e or more.

Samples 1-5, 1-6, 1-7, 1-1
Reference numerals 0 and 1-11 are the present example and the comparative example in which the ion current of the assist beam is variously changed. From these experimental results, the ion current of the assist beam must be in the range of 5 to 15 mA (Samples 1-5 and 1-10).
You can see that.

Samples 1-5 and 1-7 ...
1-9, and the experimental results of the samples 1-12, the acceleration voltage of the assist beam be a too high 180EV, also it can be seen that not have sufficient H _ua be as low as 50 eV. Therefore, it can be seen that this accelerating voltage must be in the range of 60 to 150 eV.

FIG. 7 shows the relationship between the change in O ₂ flow rate and the degree of oxidation x = O / Fe when the flow rate of Ar + O ₂ gas in the assist gun is fixed at 10 sccm. In this figure, for example, when the O ₂ flow rate is 4 sccm, the Ar flow rate is 6 sccm. Here in order to examine the effect of antiferromagnetic FeO _X is, FeO _x (10 from the substrate side
The evaluation was performed using a film in which 00Å) -NiFe (38Å) -Cu (88Å) were stacked in this order. As is clear from the result of FIG. 7, x is in the range of 1.35 to 1.55 when the O ₂ flow rate is 1 to 5 sccm. That is, A
r: O ₂ flow ratio 1: 1 to 9: x becomes within the range of 1.35 to 1.55 at 1, and also the value of H _ua 4
It was confirmed that the value was a large value of 0 Oe or more.

In FIG. 8, the flow rates of Ar and O ₂ gas in the assist beam are (7, 3), (6, 4), (5,
5) Three types of parameters (each of which is in sccm) are shown, and experimental results are shown for each of these parameters, in which the relationship between the ion current change of the assist beam and the unidirectional anisotropy _Hua is _investigated . The laminated film structure is such that FeO _x (1000Å) -NiFe (38Å) -Cu from the substrate side.
The evaluation was performed using a film laminated in the order of (88Å).
The acceleration voltage of the assist beam at this time is fixed at 100 eV. From the figure, it can be seen that although there is some difference depending on the Ar: O ₂ flow rate ratio, a large unidirectional anisotropy is exhibited in the ion current range of 5 to 15 mA.

Since the point of the present invention lies in the formation of iron oxide FeO _x exhibiting antiferromagnetism, the identification of the physical properties of the material will be described below.

[0126] Table result of thin film X-ray diffraction of samples 1-5 the value of H _ua showed 110Oe among 1 is shown in FIG. From this result, although broad, a diffraction peak from the α-phase (104) oriented surface of hematite is confirmed.
Since no other diffraction peaks of iron oxide such as magnetite and wustite are confirmed, αFe is used as a pinning layer.
_It can be seen that ₂ O ₃ (hematite) is generated.
As a result, a large value of H _ua that 110Oe is obtained.

Sample 1-2 (Table 1) was cut in the stacking direction, and the stacking section was cut by a high-resolution electron microscope (TE).
M). Then, as a result of examining the inside of the pinning layer 50 by electron diffraction, the existence of a hematite phase was confirmed. Further, in this case, it was found that, in addition to the hematite phase, 40 vol% magnetite phase was also mixed.
However, due to the hematite phase present in a proportion of 60% by volume, the value of _Hua was practically sufficient. In other samples, hematite phase is 30% by volume
In addition to that, a 70 volume% magnetite phase and a small amount of wustite phase were also confirmed. It was confirmed that the value of _Hua was not so large, but it was _manageable within the range that could be practically used as a head. . From these results,
It was found that the pinning layer is not limited to a single layer of hematite, and may be any layer containing at least 30% by volume and 60% by volume or less of αFe ₂ O ₃ (hematite) exhibiting antiferromagnetism.

In addition, for other samples having different film forming conditions,
In particular, the inside of the pinning layer 50 was similarly observed with a high resolution electron microscope (TEM). Then, the pinning layer 50
The inside of was a single phase of hematite phase, but the crystal was a collection of 60 to 100Å fine crystal grains of hematite crystal. At this time, the value of H _ua is a 71Oe, but not too well, it was confirmed that the degree no practical problem. Therefore, the pinned layer is αFe which exhibits antiferromagnetism.
100 Å or less of ₂ O ₃ (hematite), especially 60-1
It is understood that a collection of 00Å microcrystals may be used.

Here, iron oxide Fe which actually exhibits antiferromagnetism
It will be described whether O _x is generated. First,
FIG. 10 is a graph showing the heat resistance of Sample 1-5 in Table 1. The value of _Hua decreases with increasing measurement temperature,
It became almost 0 at about 200 ° C. This is antiferromagnetic F
The eO _x shows that as the Neel temperature of this layer approaches, its pinning effect diminishes and eventually the pinning effect is lost. From this result, it was confirmed that the formed iron oxide FeO _x was antiferromagnetic and that its Neel temperature was 200 ° C. Further, as a result of conducting the same evaluation on FeO _x samples under various film forming conditions, the Neel temperature of this pinning layer is 1
It was found to be in the range of 20 ° C to 400 ° C.

From the above results and the results shown in Table 1, 1.35 ≦ x ≦ 1.5 of iron oxide FeO _x was used as the pinning layer.
5. It is understood that by forming the unit of atomic ratio and thickness of 100Å to 3000Å, the magnetization direction of the adjacent ferromagnetic layer can be pinned. Further, this pinning layer contains αFe ₂ O ₃ (hematite) exhibiting antiferromagnetism or αFe ₂ O ₃ (hematite) exhibiting antiferromagnetism at least 30% by volume or more and 60% by volume or less, antiferromagnetic Indicating αF
e ₂ O ₃ (hematite), which is a collection of fine crystals of 100 Å or less, shows antiferromagnetism and its Neel temperature is 120
It can be seen that the same effect can be obtained with any of those whose temperature is between 400 ° C and 400 ° C. These iron oxides FeO _x exhibit antiferromagnetism by being produced by sputtering an iron oxide target by an ion beam sputtering method and irradiating the substrate with an assist beam of a mixed gas of Ar and O _2. A pinning layer having a pinning effect can be formed.

The characteristic evaluation common to each of the present invention will be described below. The BH loop was measured by a vibrating magnetometer. For resistance measurement, a sample having a shape of 0.4 × 6 mm was prepared from the sample having the configuration shown in Table 1, and an external magnetic field was applied in a plane perpendicular to the current,
The resistance when changing from 300 to 300 Oe was measured by the four-terminal method. From the resistance, the minimum value ρsat of the specific resistance and the MR change rate ΔR / R were determined. MR change rate ΔR / R
Was calculated by the following formula, where ρmax is the maximum specific resistance and ρsat is the minimum specific resistance: ΔR / R = (ρmax −ρsat) × 1
00 / ρsat (%). Further, a differential curve of the measured MR curve was taken, and the maximum value near the zero magnetic field was taken as the MR slope (unit:% / Oe) to evaluate the rising characteristics. 1 MHz
As described above, the value of the MR slope in the high-frequency magnetic field of 6 Oe width needs to be 0.7% / Oe or more.

Table 2 below shows the constitution and magnetoresistance change rate of the spin-valve type magnetic multilayer film showing MR change formed by using the above pinned layer.

[0133]

[Table 2] In Table 2, for example, the sample 2-1 is [αF
_{e 2 O 3 (1000) -CoNiFe} (32) -Cu
(22) -NiFeCo (77)], an antiferromagnetic layer (pinning layer) of αFe ₂ O _{3 having} a thickness of 1000 Å from the substrate side, a CoNiFe alloy layer having a thickness of 32 Å used as a ferromagnetic layer, and a layer having a thickness of 22 Å Cu non-magnetic metal layer, 77Å thick Ni
It is a magnetic multilayer film in which soft magnetic layers of FeCo are sequentially arranged. The materials constituting each sample are the antiferromagnetic layer (pinned layer), the ferromagnetic layer, the nonmagnetic metal layer, and the soft magnetic layer in this order (m
1, m2, m3, m4). Further, the thicknesses of these layers are shown in Table 2 in the same order (t1, t2, t3, t4). In addition, CoNiF used as the ferromagnetic layer
The composition of the e alloy layer is Co _{8 8} Ni ₆ Fe ₆ , and the composition of the NiFeCo alloy layer used as the soft magnetic layer is Ni ₄₈ Fe ₁₇ Co.
₃₅ (wt% each). Unless otherwise specified in the following examples, the composition of the CoNiFe and NiFeCo layers is the same as that of this example. In addition, the MR slope in a DC magnetic field and the MR slope in a 6 Oe width in a high frequency magnetic field at 1 MHz (unit:% / Oe) are also shown. This value must be 0.7% / Oe or more as described above.

The CoNiFeSiB alloy layer in Sample 2-3 and Sample 2-4 shown in Table 2 is an amorphous soft magnetic layer, and its composition is Co ₇₀ Ni ₅ Fe ₅
This is an example in the case of Si ₈ B ₁₂ (atomic%).

Sample 2-5 is an example in which an Fe ₂ O ₃ layer containing 50% by volume of a hematite layer was used as a pinning layer.

Samples 2-8 and 2-9 (both comparative examples) have the same multilayer film structure as sample 2-1.
This is an example when the layer thicknesses (t3) of the nonmagnetic metal layers are different.
That is, in Sample 2-8, the nonmagnetic metal layer thickness is too large, and the MR change rate is reduced. On the other hand, in 2-9, on the contrary, the thickness of the non-magnetic metal layer is too thin, and the ferromagnetic coupling between the two magnetic layers becomes strong, so that the relative angle of spin does not occur, and as a result, a spin valve MR change is shown. It's gone.

Sample 2-10 (Comparative Example) has the same multilayer film structure as Sample 2-1, but is an example in which the layer thickness (t1) of the pinning layer is different. That is, in Sample 2-10, the pinning layer was too thin and the MR change rate was reduced. This is because the antiferromagnetism of iron oxide FeO _x is not sufficiently realized due to the thin pinning layer.

Samples 2-11 and 2-12 (both comparative examples) have substantially the same multilayer film structure as sample 2-1 except that the thicknesses of the two magnetic layers are out of the range of the present invention. Here is an example. That is, in Sample 2-11, the layer thickness (t4) of the soft magnetic layer was too thick, and the specific resistance of the multilayer film was large, and as a result, the MR change rate was small. In the sample 2-12, the layer thickness (t2) of the ferromagnetic layer is too thick,
In this example, the energy of the pinned layer is insufficient and the spin of the ferromagnetic layer is not sufficiently pinned. As a result, the MR change rate is not sufficient in both samples.

From the results shown in Table 2 above, the antiferromagnetic characteristics of iron oxide FeO _x , which is the pinning layer, are sufficiently realized, and the materials of the ferromagnetic layer, the soft magnetic layer, and the nonmagnetic metal layer are
And their layer thicknesses selected from the ranges disclosed in the present invention, the 6O in a high frequency magnetic field at 1 MHz.
It can be seen that the magnetoresistive effect element in which the gradient of the change in the magnetic resistance in the e width is 0.7% / Oe or more can be realized.

11A and 11B show the MR curve and the magnetization curve of the spin-valve magnetic multilayer film which constitutes Sample 2-1 in Table 2, respectively. The spin of the ferromagnetic layer is pinned by the hematite exhibiting antiferromagnetism, and a spin valve type MR curve which is asymmetrical to the left and right is obtained. Similarly, the magnetization curve is also asymmetric in the upper and lower directions due to the pinning effect. The same sample 10 is shown in FIG.
A minor loop below Oe is shown. 0 magnetic field to M
It can be seen that the R curve rises sharply. The maximum hysteresis width in this minor MR loop is as small as about 3 Oe, which shows extremely good characteristics.

Further, in FIG. 13, [αFe ₂ O ₃ (1000Å) -CoNiFe (45) formed on a glass substrate was used.
Å) -Cu (88Å)] The heat treatment result of the multilayer film sample is shown. This is a sample hematite layer and a ferromagnetic layer exhibiting antiferromagnetism exchange-coupled, the heat treatment results, H _ua
It is confirmed that the value of is increasing. The improvement in the characteristics is up to 50% in the heat treatment for 2 hours.
That is, it is understood that the spin valve characteristic can be greatly improved by the heat treatment.

Further, FIG. 14 shows a change in the X-ray diffraction pattern when iron oxide FeO _x as a pinning layer is formed on the substrate, the substrate is taken out from the film forming apparatus, and heat treatment is performed in the atmosphere. Is shown. The temperature was maintained at 200, 300, and 400 ° C. in this order for 4 hours, and the heat treatment was accumulated. From these results, it can be seen that the diffraction peak from the (104) -oriented plane of hematite, which clearly shows antiferromagnetism, is large, and crystallization of hematite is progressing. After that, when the substrate was set again in the vacuum film forming apparatus and a film having a spin valve structure was further formed, it was confirmed that a larger MR change rate and a larger _Hua were obtained as compared with the sample which was not subjected to the heat treatment. . Therefore,
After forming the magnetoresistive effect film, 100 ℃ ~ 300 ℃
The heat treatment may be carried out at the temperature of 10 ° C., or at least the pinning layer is formed on the substrate and then the heat treatment is carried out at a temperature of 100 ° C. to 300 ° C., and then the spin valve film (magnetoresistive element) is formed. Good.

Then, as shown in FIG. 18, the oxygen blocking layer 4 is provided between the pinning layer 50 and the ferromagnetic layer 40.
A specific embodiment of the invention of the magnetoresistive effect element having the magnetic multilayer film 1 with the interposition of 5 will be shown as a second embodiment.

Example 2 A glass substrate was used as a substrate, this was placed in a radio frequency sputtering (RF sputtering) apparatus, hematite was used as a target, and an αFeO _x film as a pinning layer 50 was formed on the glass substrate. did. In forming the ArufaFeO _X film, ultimate pressure ^{6 × 10 -7 Torr~8 × 10 -7} Torr, the pressure 7.5 × 10 ^-3 Torr during the deposition, the substrate temperature 14 ° C. about and,
The flow rates of Ar and O ₂ were changed in the range of 0.5 to 8 sccm, and the specific O ₂ flow rate ratio was as shown in Table 3 below. The input power was 150 to 170 W (watt). After forming the αFeO _x film under these conditions, a Co film as the oxygen blocking layer 45, a NiFe film as the ferromagnetic layer 40, and a Ta (tantalum) film as the protective layer were then formed. The film thickness of each of these layers is as shown in Table 3 below.

The film forming rate of each material is 0.2 to 10
The sputtering rate was set to about Å / sec and the magnetic field was applied in the plane of the substrate and in the direction parallel to the measurement current during film formation. Then, after forming each layer, it was cooled from 200 ° C. in a vacuum of 10 ⁻⁵ Torr while applying a magnetic field of 200 Oe in the in-plane direction at right angles to the measurement current to induce the pinning effect of the ferromagnetic layer. . In this way, samples 3-1 to 3-5 of the magnetoresistive effect element as shown in Table 3 were prepared. For each of these samples, αFeO _X film oxidation degree X (= O /
Fe), Hua, and heat resistant temperature were measured. The heat resistant temperature is 80 ° C. and 110 ° C. in a vacuum of 10 ⁻⁶ to 10 ⁻⁵ Torr.
℃, 140 ℃, 170 ℃, 200 ℃, 250 ℃, 300
The film was stored for 1 hour at each temperature while applying a magnetic field in the same direction as the film formation, and then cooled to room temperature. Then, the magnetization curves of these samples are measured, and the shift amount from the 0 magnetic field of the curves, that is, Hua
Was evaluated. Then, a decrease curve of Hua was drawn, and the point at which Hua became 0 was determined from this curve and set as the heat resistant temperature.

The results are shown in Table 3 below.

[0147]

[Table 3] From the results shown in Table 3, when the αFeO _x film was formed, A
By setting the oxygen flow rate in the mixed gas of r and O ₂ to 20 to 40%, a film having an oxidation degree X in a predetermined range can be obtained, and a magnetic multilayer film including this film has a large Hua and is extremely excellent. It can be seen that it has excellent heat resistance. Further, when the X-ray diffraction pattern of the αFeO _x film produced under the high frequency sputtering conditions of the present invention was examined, it was found that hematite was formed (1
Only the 04) peak and the (006) peak were confirmed.

Further, an experiment was conducted to show the effect of interposing the oxygen blocking layer 45 between the pinning layer (αFeO _x ) and the ferromagnetic layer in the present invention. That is, as a sample, a 1000 Å thick αFe ₂ O ₃ film, a 5 Å thick Co film (oxygen blocking layer), and a 95 Å thick N film were formed on a substrate.
An iFe film, a sample in which a Ta film having a thickness of 100 Å is sequentially formed, an αFe ₂ O ₃ film having a thickness of 1000 Å, a Co film (oxygen blocking layer) having a thickness of 10 Å, a NiFe film having a thickness of 90 Å, on a substrate, A sample in which a Ta film having a thickness of 100 Å is sequentially formed, and a sample in which an αFe ₂ O ₃ film having a thickness of 1000 Å, a NiFe film having a thickness of 100 Å, and a Ta film having a thickness of 100 Å are sequentially formed on a substrate. Each was produced.

These samples were heat-treated under various temperature conditions, and the relative change in the unidirectional exchange anisotropy energy J at the interface of the pinning layer (αFeO _x ) was determined based on the state during film formation. . That is, for each sample,
Unidirectional exchange anisotropy after heat treatment at a temperature of 0 ° C, 200 ° C, 250 ° C, and 300 ° C for 1 hour in a vacuum of 5 × 10 ^{-6 to} 20 × 10 ^-6 Torr, respectively. The relative change of energy J was investigated. The unidirectional exchange anisotropy energy J is represented by J = Hua · Ms · d and represents the magnitude of exchange coupling in the antiferromagnetic layer. Hua represents unidirectional anisotropy, Ms represents the saturation magnetization of the ferromagnetic layer, and d represents the thickness of the ferromagnetic layer.

The results are shown in the graph of FIG. From the graph shown in FIG. 19, the sample in which the Co film (oxygen blocking layer) is interposed retains sufficient characteristics even at the heat treatment of 250 ° C. On the other hand, the N film is directly added to the αFe ₂ O ₃ film without interposing a Co film (oxygen blocking layer).
The characteristics of the sample having the iFe film formed thereon are already deteriorated by heat treatment at 150 ° C.

Furthermore, two types of magnetic multilayer film samples exhibiting spin-valve characteristics were formed, and the relationship between the heat treatment temperature and the MR change rate was investigated for these samples, and the results are shown in the graph of FIG. As a sample, on the substrate, an αFe ₂ O ₃ film having a thickness of 1000 Å, a Co film having a thickness of 20 Å (having both functions of an oxygen blocking layer and a ferromagnetic layer), a Cu film having a thickness of 25 Å (a non-magnetic metal) Layer), a laminated body of a Co film having a thickness of 10Å and a NiFe film having a thickness of 50Å (soft magnetic layer), a Co film having a thickness of 20Å, a thickness of 100
A sample with a Å Ta film sequentially formed, and a 1000 Å thick αFe ₂ O ₃ film, a 38 Å NiFe film (ferromagnetic layer), and a 27 Å Cu film (non-magnetic metal layer) on the substrate. ), A NiFe film (soft magnetic layer) having a thickness of 77Å and a Cu film having a thickness of 30Å were sequentially formed.

In this case, 5 × 10 ^{-6 to} 20 × 10 ^-6 Torr
Samples in vacuum at 1 at each given temperature
Heat treatment (annealing treatment) was performed for 5 minutes each. As can be seen from the graph shown in FIG. 20, the sample using the Co film having the functions of both the oxygen blocking layer and the ferromagnetic layer shows almost no deterioration in the MR characteristics even at the heat treatment of 250 ° C. On the other hand, the sample provided with the NiFe ferromagnetic film instead of the Co film is 15
The MR change rate is greatly reduced by the heat treatment at 0 ° C. or higher.
Further, from FIG. 20, it can be seen that the MR change rate is approximately tripled by using the Co film having both the functions of the oxygen blocking layer and the ferromagnetic layer instead of the NiFe ferromagnetic layer. Therefore, if this material is used as the material for the MR head for reading of ultra-high density magnetic recording, there is a great merit.

Next, various spin-valve type magnetic multilayer films exhibiting MR change formed by using the pinning layer 50 of the αFeO _x film as described above were prepared, and predetermined properties shown in Table 4 below were investigated. It was

[0154]

[Table 4] In Table 4, for example, sample 4-2 is [α
Fe ₂ O ₃ (1000) -Co (6) -NiFe (2
0) -Cu (25) -Co (8) -NiFe (60)]
The antiferromagnetic layer (pinning layer) of αFe ₂ O _{3 having} a thickness of 1000 Å from the substrate side, the Co layer having a thickness of 6 Å used as the oxygen blocking layer, and the NiFe (Ni _{81 having a} thickness of 20 Å used as the ferromagnetic layer). Fe ₁₉ : wt%) layer, 25Å thick Cu
Is a magnetic multi-layered film in which a non-magnetic metal layer, a laminated body of 8Å thick Co used as a soft magnetic layer, and a 60Å thick NiFe (Ni ₈₁ Fe ₁₉ : wt%) are sequentially arranged. In the following examples, NiFe is Ni ₈₁ Fe unless otherwise specified.
₁₉ (% by weight) is shown.

Further, in Table 4, the item of the O ₂ gas flow rate ratio (%) shows the condition of the gas atmosphere of the high frequency sputtering at the time of forming the αFe ₂ O ₃ layer, and the degree of oxidation X (= O / Fe). ) Indicates the actually measured degree of oxidation of the αFe ₂ O ₃ layer. The evaluation items shown in Table 4 are substantially the same as those in Table 2 above, but in Table 4, the data after the heat treatment at 250 ° C. are also shown.

As described above, from the results shown in Table 4, the antiferromagnetic characteristics of the iron oxide FeO _x , which is the pinning layer, are sufficiently realized, and the ferromagnetic layer (including the blocking layer), the soft magnetic layer, the non-magnetic layer By selecting the material of the magnetic metal layer and the layer thickness thereof from the range disclosed in the present invention, the gradient of the magnetoresistance change in the 6 Oe width in the high frequency magnetic field at 1 MHz is 0.7% / Oe or more. It is understood that the following magnetoresistive effect element can be realized. In addition, those within the scope of the present invention include
It can be seen that there is little change in properties after heat treatment at 250 ° C. and that the heat resistance is extremely excellent.

Furthermore, as examples and comparative examples of the invention of the MR head as the magnetic conversion element, the following examples 3 to 3 are given.
5 and Comparative Example 1 are shown.

Example 3 FeAlSi (sendust) of 2 μm was formed as a layer corresponding to the lower shield on an AlTiC (AlTiC) substrate.
a film having a thickness of m (corresponding to reference numeral 300 in the lower part of FIG. 4),
Al ₂ O ₃ is deposited on top of this as an insulating layer (gap film) 15
A film is formed to a thickness of 00Å, and αFe ₂ O ₃ (100
0Å) -CoNiFe (26Å) -Cu (24Å) -N
Each layer was laminated in the order of iFeCo (86) to form a spin valve magnetic multilayer film. Film formation conditions are ultimate pressure of 2.3 ×
10 ^-7 Torr, deposition pressure 1.4 x 10 ^-4 Torr, substrate temperature 14 ° C, each material is deposited at a deposition rate of 0.2 to 0.3 Å / sec, and a magnetic field is applied to the substrate during deposition. The film was formed by the ion beam sputtering method while being applied in the plane and parallel to the measurement current.

Thereafter, a pattern of 20 μm × 6 μm was formed as a magnetically sensitive portion by using the photolithography technique, and an electrode having a track width of 3 μm was formed thereon. On top of that, Al ₂ O ₃ is used as an insulating layer (gap film) in an amount of 15
It is formed to a thickness of 00Å, and the upper shield layer N
iFe (permalloy) was formed to a thickness of 2 μm (corresponding to reference numeral 300 in the upper part of FIG. 4) to obtain an MR head. Made M
The structure of the R head is as shown in FIG. Then 1
In a vacuum of 0 ^-5 Torr, cooling from 180 ° C while applying a magnetic field of 200 Oe in the in-plane direction at right angles to the measurement current direction,
The pinning effect of the ferromagnetic layer was induced. Measuring current 5mA,
FIG. 15 shows changes in the output voltage when the external magnetic field is changed within a range of ± 20 Oe and 50 Hz. In the MR head using the artificial lattice magnetic multilayer film according to the present invention, the normalized output voltage per unit track width is about 830 μV / μm.
The output voltage of was obtained.

Comparative Example 1 As Comparative Example 1, permalloy was used under the same conditions as in Example 3 above to fabricate an MR head utilizing the conventionally used anisotropic magnetoresistive effect. The measurement current was 5 mA, and the external magnetic field was changed in the range of ± 20 Oe and 50 Hz. The output voltage at this time was about 170 μV / μm.

Comparing Example 3 with Comparative Example 1, in the MR head of the present invention, an output nearly five times higher than that of the conventional example was obtained. Therefore, the effect of the present invention is clear.

Embodiment 4 Further, FIG. 16 shows an example in which the magnetoresistive effect element of the present invention is applied to a yoke type MR head. Here, a notch is provided in a part of the yokes 600, 600 for guiding the magnetic flux, and the magnetoresistive effect element 200 has a thin insulating film 40 therebetween.
0 is formed. This magnetoresistive element 20
At 0, electrodes (not shown) for passing a current in a direction parallel to or perpendicular to the magnetic path formed by the yokes 600, 600 are formed. As a result, it was confirmed that the output was double that of the MR head using Permalloy. Since the magnetic multilayer film of the present invention has a good rising characteristic at zero magnetic field, it is not necessary to provide a shunt layer or a bias magnetic field applying unit which is usually used.

Embodiment 5 FIG. 17 shows another embodiment in which a magnetic conversion element, for example, an MR head is constructed using the magnetoresistive effect element of the present invention. The magnetoresistive effect element 200 is formed in magnetic contact with the high resistivity flux guide layers 700 and 710. This flood guide layer is a magnetic multilayer film 200.
The measurement current flowing through the magnetic multilayer film 200 does not substantially flow through the flux guide layers 700 and 710 because it is made of a material having a specific resistance that is three times or more higher. On the other hand, the flux guide layer 700 and the magnetic multilayer film 20
Since it is in magnetic contact with 0, the signal magnetic field is guided to the flux guide layer 700 and does not lose its strength.
The magnetic multilayer film 200 is reached. Reference numeral 600 denotes another different flux guide layer, which functions as a return guide for the magnetic flux that has passed through the magnetic multilayer film 200. The flux guide layer 600 may be provided on both sides of the magnetoresistive effect element 200 and the high resistivity flux guide layers 700 and 710. Further, the guide layers 710 and 600 may be in contact with the medium at the far end.
At this time, 3 from the MR head when using Permalloy.
Double output was confirmed. In the figure, reference numeral 400 is a non-magnetic insulating layer.

[0164]

As described above, according to the present invention relating to the magnetoresistive effect element, the use of iron oxide FeO _x exhibiting antiferromagnetism as the pinning layer results in particularly excellent corrosion resistance and high frequency of 1 MHz. A spin-valve type magnetoresistive effect element having an MR gradient in a magnetic field region of 0.7% / Oe or more and a resistance change rate can be obtained. Moreover, the rising characteristics of the MR curve at 0 magnetic field are extremely good, the hysteresis is small, and in addition, high heat resistance is exhibited. Regarding this heat resistance, the effect is further improved by further interposing an oxygen blocking layer between the pinning layer and the ferromagnetic layer. A magnetic conversion element using a magnetoresistive effect element having a magnetic multilayer film, for example, an MR head, can obtain an output voltage that is about five times as large as that of a conventional material. Therefore, it is possible to provide a highly reliable MR head capable of reading super-high density magnetic recording exceeding 1 Gbit / inch ² .

[Brief description of the drawings]

FIG. 1 is a sectional view of a magnetoresistive element according to the present invention.

FIG. 2 is a schematic view of the structure of a magnetoresistive element, particularly a magnetic multilayer film, for explaining the operation of the present invention.

FIG. 3 is a schematic diagram of a magnetization curve and an MR curve for explaining the operation of the present invention.

FIG. 4 is a partially omitted sectional view showing an example of a magnetic conversion element of the present invention.

FIG. 5 is a sectional view showing the structure of a magnetoresistive element (magnetic multilayer film) and an electrode section of the magnetic transducer of the present invention.

FIG. 6 is a cross-sectional view showing another example of the structure of the magnetoresistive effect element (magnetic multilayer film) and the electrode portion of the magnetic conversion element of the present invention.

FIG. 7 is a graph showing the relationship between the O ₂ flow rate of the assist beam and the degree of oxidation of the pinning layer in the magnetoresistive effect element (magnetic multilayer film) of the present invention.

FIG. 8 is a graph showing a relationship between an ion current of an assist beam and a unidirectional anisotropic magnetic field in the magnetoresistive effect element (magnetic multilayer film) of the present invention.

FIG. 9 is a graph showing an X-ray diffraction pattern of a pinning layer in the magnetoresistive effect element (magnetic multilayer film) of the present invention.

FIG. 10 is a graph showing changes in unidirectional anisotropic magnetic field with respect to temperature in the magnetoresistive effect element (magnetic multilayer film) of the present invention.

11A and 11B are graphs showing an MR curve and a magnetization curve in a DC magnetic field of the magnetoresistive effect element (magnetic multilayer film) of the present invention, respectively.

FIG. 12 is a graph showing a minor MR curve of the magnetoresistive effect element (magnetic multilayer film) of the present invention.

FIG. 13 is a graph showing the influence of the heat treatment time on the change of the unidirectional anisotropic magnetic field in the magnetoresistive effect element (magnetic multilayer film) of the present invention.

FIG. 14 is a graph showing the relationship between the heat treatment time and the change in the X-ray diffraction pattern in the magnetoresistive effect element (magnetic multilayer film) of the present invention.

FIG. 15 is a chart showing an applied magnetic field and an output voltage of the magnetic conversion element (MR head) of the present invention.

FIG. 16 is a partially omitted cross-sectional view showing an example in which the magnetoresistive effect element (magnetic multilayer film) of the present invention is applied to a yoke type MR head.

FIG. 17 is a graph showing a magnetoresistive element (magnetic multilayer film) of the present invention applied to a flux guide type MR head.
It is a partially omitted sectional view showing an example.

FIG. 18 is a cross-sectional view showing another embodiment of the magnetoresistive effect element of the present invention.

FIG. 19 is a graph showing the relationship between the annealing temperature (heat treatment temperature) and the relative change in J value in the magnetic multilayer film sample.

FIG. 20 is a magnetoresistive effect element (magnetic multilayer film).
Annealing temperature (heat treatment temperature) and MR of sample
It is a graph which shows the relationship with a rate of change.

FIG. 21 is a schematic perspective view showing a suitable connection state between the magnetoresistive effect element (magnetic multilayer film) and the electrode portion of the magnetic conversion element of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Magnetic multilayer film 3 ... Magnetoresistance effect element 5 ... Substrate 20 ... Soft magnetic layer 30 ... Non-magnetic metal layer 40 ... Ferromagnetic layer 50 ... Pinning layer 80 ... Protective layer 90 ... Recording medium 93 ... Recording surface 150 ... Magnetic Resistance effect type head 200 ... Magnetoresistance effect element

Claims (60)

[Claims] 1. A magnetic conversion element including a magnetoresistive effect element, a conductor film, and an electrode portion, wherein the conductor film is electrically connected to the magnetoresistive effect element through the electrode portion, The magnetoresistive element includes a non-magnetic metal layer, a ferromagnetic layer formed on one surface of the non-magnetic metal layer, a soft magnetic layer formed on the other surface of the non-magnetic metal layer, and the ferromagnetic layer. A magnetic multilayer film having a pinning layer formed on the ferromagnetic layer (the surface opposite to the surface in contact with the nonmagnetic metal layer) in order to pin the direction of magnetization of the The layer is FeO _x (1.35 ≦ x ≦ 1.55,
A magnetic conversion element, characterized in that the unit is an atomic ratio. 2. The magnetoresistive effect element has a substrate,
The magnetic conversion element according to claim 1, wherein the pinning layer, the ferromagnetic layer, the nonmagnetic metal layer, and the soft magnetic layer are sequentially stacked from the substrate side. 3. The pinning layer has a thickness of 100Å to 3
The magnetic conversion element according to claim 1 or 2, wherein the magnetic conversion element has a thickness of 000Å. 4. The pinned layer is αF exhibiting antiferromagnetism.
e ₂ O ₃ (hematite).
The magnetic conversion element according to any one of 1. 5. The pinned layer is αF exhibiting antiferromagnetism.
The magnetic conversion element according to any one of claims 1 to 3, which contains at least 30% by volume and not more than 60% by volume of e ₂ O ₃ (hematite). 6. The pinned layer is αF exhibiting antiferromagnetism.
The magnetic conversion element according to claim 1, wherein the magnetic conversion element is a collection of fine crystals of e ₂ O ₃ (hematite) of 100 Å or less. 7. The magnetic conversion element according to claim 1, wherein the pinning layer exhibits antiferromagnetism and its Neel temperature is 120 ° C. to 400 ° C. 8. The pinning layer is formed by sputtering an iron oxide target by an ion beam sputtering method,
The magnetic conversion element according to any one of claims 1 to 7, which is a film formed while being irradiated with an assist beam of a mixed gas of Ar and O ₂ . 9. The assist beam has an acceleration voltage of 60.
˜150 eV, ionic current 4˜15 mA, Ar: O ₂
Flow rate ratio of 1: 1 to 9: 1, Ar + O ₂ flow rate of 6 to ₂
The magnetic conversion element according to claim 8, which is operated in a range of 0 sccm. 10. The pinning layer is a film formed by sputtering an iron oxide target in a mixed gas atmosphere of Ar and oxygen by a high frequency sputtering method, and the oxygen gas flow rate during film formation is the total gas flow rate. The magnetic conversion element according to any one of claims 1 to 7, which is a film formed by adjusting the film thickness in the range of 20 to 40%. 11. The ferromagnetic layer is (Co _z Ni _1-z ).
_w Fe _1-w (however, 0.4 ≦ z ≦ 1.0 by weight, 0.
5 ≦ w ≦ 1.0), and the soft magnetic layer is (Ni _x Fe _1-x ) _y Co _1-y (however, 0.7 ≦ x ≦ 0. 9, 0.1 ≦ y ≦ 0.5)
The magnetic conversion element according to claim 1, which has a composition represented by: 12. The ferromagnetic layer is (Co _z Ni _1-z ).
_w Fe _1-w (however, 0.4 ≦ z ≦ 1.0 by weight, 0.
5 ≦ w ≦ 1.0 and which) a composition represented by, the soft magnetic _{layer, Co t M u M 'q} B r ( provided that an atomic ratio of 0.6 ≦ t ≦ 0.95,0 0.01 ≤ u ≤ 0.2, 0.0
1 ≦ q ≦ 0.1, 0.05 ≦ r ≦ 0.3; M is Fe,
At least one selected from Ni, M'is
The magnetic conversion element according to any one of claims 1 to 10, which has a composition represented by at least one selected from Zr, Si, Mo, and Nb). 13. The magnetic conversion element according to claim 1, wherein the nonmagnetic metal layer is made of a material containing at least one selected from Au, Ag, and Cu. 14. The magnetoresistive element according to claim 1, which exhibits a spin valve type magnetoresistive change due to pinning of magnetization of a ferromagnetic layer by a pinning layer. Magnetic conversion element. 15. The magnetoresistive effect element according to claim 1, wherein a gradient of magnetoresistance change in a width of 6 Oe in a high frequency magnetic field at 1 MHz is 0.7% / Oe or more.
4. The magnetic conversion element according to any one of 4 above. 16. The magnetic conversion element according to claim 1, wherein the magnetic conversion element is a magnetoresistive head. 17. The magnetic conversion element according to claim 16, wherein both end portions of the magnetoresistive effect element are joined in a state where the entire end portion is in contact with the electrode portion. 18. A soft magnetic layer for coupling is further provided between the magnetoresistive effect element and electrode portions formed at both ends thereof, and the soft magnetic layer for coupling and the end portion of the magnetoresistive effect element are entirely formed. 17. The magnetic conversion element according to claim 16, wherein the magnetic conversion elements are connected in contact with each other. 19. The connecting soft magnetic layer is continuous between the magnetoresistive effect element and the electrode portions formed at both ends of the magnetoresistive effect element, and in contact with the lower surface of the electrode portion. The magnetic conversion element according to claim 16, wherein the magnetic conversion element is formed as follows. 20. The magnetic conversion element according to claim 16, which does not have a bias magnetic field applying mechanism. 21. The ferromagnetic layer is formed by applying an external magnetic field of 10 to 300 Oe in the in-plane direction, which is the same as the signal magnetic field direction, during the film formation. 21. The magnetic conversion element according to claim 16, which is formed by applying an external magnetic field of 10 to 300 Oe in the in-plane direction perpendicular to the signal magnetic field direction during the film formation. 22. A magnetoresistive effect element formed by stacking layers,
The heat treatment is performed at a temperature of 100 ° C to 300 ° C.
The magnetic conversion element according to any one of claims 6 to 20. 23. The magnetoresistive effect element, wherein at least a pinning layer is formed on a substrate, and then 100 ° C. to 300 ° C.
21. The heat treatment is performed at the temperature of 20.
The magnetic conversion element according to any one of 1. 24. A non-magnetic metal layer, a ferromagnetic layer formed on one surface of the non-magnetic metal layer, a soft magnetic layer formed on the other surface of the non-magnetic metal layer, and a ferromagnetic layer of the ferromagnetic layer. A magnetoresistive effect element comprising a magnetic multilayer film having a pinning layer formed on a ferromagnetic layer (a surface opposite to a surface in contact with a nonmagnetic metal layer) for pinning the magnetization direction. The pinning layer is FeO _x (1.35 ≦ x ≦ 1.55,
A magnetoresistive effect element characterized in that the unit is an atomic ratio. 25. The magnetoresistive effect element further has a substrate, and the pinning layer, the ferromagnetic layer, and
The magnetoresistive effect element according to claim 24, wherein the non-magnetic metal layer and the soft magnetic layer are sequentially stacked. 26. The pinning layer has an antiferromagnetic property of α
The magnetoresistive effect element according to claim 24 or 25, which is Fe ₂ O ₃ (hematite). 27. The pinned layer has an antiferromagnetic property of α
26. The magnetoresistive effect element according to claim 24 or 25, containing at least 30% by volume and not more than 60% by volume of Fe ₂ O ₃ (hematite). 28. The pinned layer has an antiferromagnetic property α
26. The magnetoresistive effect element according to claim 24 or 25, which is a collection of fine crystals of Fe ₂ O ₃ (hematite) having a volume of 100 Å or less. 29. The pinned layer exhibits antiferromagnetism,
The nail temperature is 120 ° C to 400 ° C.
Alternatively, the magnetoresistive effect element according to claim 25. 30. The pinning layer is a film formed by sputtering an iron oxide target by an ion beam sputtering method and irradiating the substrate with an assist beam of a mixed gas of Ar and O _2. 30. The magnetoresistive effect element according to claim 24. 31. The assist beam has an acceleration voltage of 6
0 to 150 eV, ionic current 4 to 15 mA, Ar: O
_{2 has} a flow rate ratio of 1: 1 to 9: 1 and Ar + O _{2 has} a flow rate of 6 to
The magnetoresistive effect element according to claim 30, wherein the magnetoresistive effect element is operated in a range of 20 sccm. 32. The pinning layer is a film formed by sputtering a target of iron oxide in a mixed gas atmosphere of Ar and oxygen by a high frequency sputtering method, and the oxygen gas flow rate at the time of film formation is the total gas flow rate. 30. The magnetoresistive effect element according to claim 24, which is a film formed by adjusting the film thickness in the range of 20 to 40%. 33. A magnetic conversion element including a magnetoresistive effect element, a conductor film, and an electrode portion, wherein the conductor film is electrically connected to the magnetoresistive effect element via the electrode portion, The magnetoresistive element has a substrate on which a pinning layer for pinning the magnetization direction of the ferromagnetic layer, a ferromagnetic layer, a nonmagnetic metal layer, and a soft magnetic layer are sequentially stacked. The pinning layer is made of FeO _x (1.35 ≦ x ≦ 1.55,
(Unit is atomic ratio), and an oxygen blocking layer having a thickness of 4 to 30 Å made of Co or an alloy containing 80 wt% or more of Co is interposed between the pinning layer and the ferromagnetic layer. Magnetic conversion element characterized by. 34. The pinning layer has a thickness of 100Å to
The magnetic conversion element according to claim 33, wherein the magnetic conversion element has a thickness of 3000Å. 35. The pinning layer has α exhibiting antiferromagnetism.
The magnetic conversion element according to claim 33 or 34, which is Fe ₂ O ₃ (hematite). 36. The pinning layer has α exhibiting antiferromagnetism.
The magnetic conversion element according to claim 33 or claim 34, containing at least 30% by volume and not more than 60% by volume of Fe ₂ O ₃ (hematite). 37. The pinned layer has an antiferromagnetic property α
The magnetic conversion element according to claim 33 or claim 34, which is a collection of fine crystals of Fe ₂ O ₃ (hematite) of 100 Å or less. 38. The pinned layer exhibits antiferromagnetism,
The Neel temperature is 120 ° C to 400 ° C.
Alternatively, the magnetic conversion element according to claim 34. 39. The pinning layer is a film formed by sputtering an iron oxide target by an ion beam sputtering method and irradiating the substrate with an assist beam of a mixed gas of Ar and O _2. The magnetic conversion element according to any one of claims 33 to 38. 40. The assist beam has an acceleration voltage of 6
0 to 150 eV, ionic current 4 to 15 mA, Ar: O
_{2 has} a flow rate ratio of 1: 1 to 9: 1 and Ar + O _{2 has} a flow rate of 6 to
40. The magnetic conversion element according to claim 39, which is operated in a range of 20 sccm. 41. The pinning layer is a film formed by sputtering a target of iron oxide in a mixed gas atmosphere of Ar and oxygen by a high frequency sputtering method, and the oxygen gas flow rate at the time of film formation is the total gas flow rate. 39. The magnetic conversion element according to claim 33, which is a film formed by adjusting the film thickness in the range of 20 to 40%. 42. The ferromagnetic layer is (Co _z Ni _1-z ).
_w Fe _1-w (however, 0.4 ≦ z ≦ 1.0 by weight, 0.
5 ≦ w ≦ 1.0).
The magnetic conversion element according to any one of claims 3 to 41. 43. The magnetic conversion element according to claim 33, wherein the ferromagnetic layer has the same composition as the oxygen blocking layer. 44. The soft magnetic layer is composed of Co from the nonmagnetic layer side.
Alternatively, a first soft magnetic layer formed of an alloy containing 80% by weight or more of Co and (Ni _x Fe _1-x ) _y Co _1-y (where 0.7 ≦ x ≦ 0.9, 0 by weight) .1 ≦ y ≦ 0.5
The magnetic conversion element according to any one of claims 33 to 43, which is a laminated body including a second soft magnetic layer formed of a composition represented by (4). 45. The magnetic conversion element according to claim 33, wherein the nonmagnetic metal layer is made of a material containing at least one selected from Au, Ag, and Cu. 46. The magnetoresistive element according to claim 33, wherein the magnetoresistance effect exhibits a spin-valve type magnetoresistive change caused by magnetization of a ferromagnetic layer being pinned by a pinning layer. Magnetic conversion element. 47. A magnetoresistive effect element formed by stacking layers,
The heat treatment is performed at a temperature of 100 ° C to 300 ° C.
The magnetic conversion element according to any one of claims 3 to 46. 48. The magnetic conversion element according to claim 47, wherein the magnetoresistive effect element has a gradient of change in magnetoresistance in a 6 Oe width in a high frequency magnetic field of 1 MHz of 0.7% / Oe or more. 49. A magnetoresistive element comprising a substrate, on which a pinning layer for pinning the magnetization direction of a ferromagnetic layer, a ferromagnetic layer, a nonmagnetic metal layer, and a soft magnetic layer are sequentially laminated. And the pinning layer is FeO _x (1.35 ≦ x ≦ 1.55,
(Unit is atomic ratio), and an oxygen blocking layer having a thickness of 4 to 30 Å made of Co or an alloy containing 80 wt% or more of Co is interposed between the pinning layer and the ferromagnetic layer. A magnetoresistive effect element characterized by. 50. The pinning layer has a thickness of 100Å to
The magnetoresistive effect element according to claim 49, wherein the magnetoresistive effect element is 3000 Å. 51. The pinned layer has an antiferromagnetic property of α
The magnetoresistive effect element according to claim 49 or claim 50, which is Fe ₂ O ₃ (hematite). 52. The pinned layer has an antiferromagnetic property of α
The magnetoresistive effect element according to claim 49 or 50, which contains at least 30% by volume and not more than 60% by volume of Fe ₂ O ₃ (hematite). 53. The pinned layer has an antiferromagnetic property of α.
The magnetoresistive effect element according to claim 49 or claim 50, which is a collection of fine crystals of Fe ₂ O ₃ (hematite) having a volume of 100 Å or less. 54. The pinned layer exhibits antiferromagnetism,
50. The Neel temperature is 120 [deg.] C. to 400 [deg.] C.
Alternatively, the magnetoresistive effect element according to claim 50. 55. The pinning layer is a film formed by sputtering an iron oxide target by an ion beam sputtering method and irradiating the substrate with an assist beam of a mixed gas of Ar and O _2. The magnetoresistive effect element according to any one of claims 49 to 54. 56. The assist beam has an acceleration voltage of 6
0 to 150 eV, ionic current 4 to 15 mA, Ar: O
_{2 has} a flow rate ratio of 1: 1 to 9: 1 and Ar + O _{2 has} a flow rate of 6 to
The magnetoresistive effect element according to claim 55, which is operated in a range of 20 sccm. 57. The pinning layer is a film formed by sputtering a target of iron oxide by a high frequency sputtering method in a mixed gas atmosphere of Ar and oxygen, and the oxygen gas flow rate during film formation is the total gas flow rate. 55. The magnetoresistive effect element according to claim 49, which is a film formed by adjusting the film thickness in the range of 20 to 40%. 58. The ferromagnetic layer is (Co _z Ni _1-z ).
_w Fe _1-w (however, 0.4 ≦ z ≦ 1.0 by weight, 0.
5 ≦ w ≦ 1.0).
The magnetoresistive effect element according to any one of claims 9 to 57. 59. The magnetic conversion element according to claim 49, wherein the ferromagnetic layer has the same composition as the oxygen blocking layer. 60. The soft magnetic layer comprises Co from the nonmagnetic layer side.
Alternatively, a first soft magnetic layer formed of an alloy containing 80% by weight or more of Co, and (Ni _x Fe _1-x ) _y Co _1-y (where 0.7 ≦ x ≦ 0.9, 0 by weight). .1 ≦ y ≦ 0.5
The magnetoresistive effect element according to any one of claims 49 to 59, which is a laminated body including a second soft magnetic layer formed of a composition represented by