JPH1091920A - Magneto-resistance effect type head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize stable spind valve operation for a long time by establishing a spin valve head structure of impressing only a vertical bias magnetic field upon a free magnetization layer without impressing the vertical bias magnetic field upon a fixed magnetization layer. SOLUTION: This magneto-resistance effect type head is equipped with a middle area having the free magnetization layer 1 changeable in its magnetizing direction by a magnetic field from a magnetic recording medium and the fixed magrretization layer 3 having its fixed magnetizing direction and end part areas positioned at both ends of this middle area for the purpose of supplying the vertical bias magnetic field and a current to the middle area, so as to exhibit an operation by a sping valve effect. The vertical bias magnetic field is supplied only to the free magnetization layer 1 by the end part areas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive head for reading information from a magnetic recording medium (hereinafter, simply referred to as "medium") by utilizing a magnetoresistive effect.

[0002]

2. Description of the Related Art With the miniaturization and large capacity of media,
Since the relative speed between the read magnetic head and the medium has become smaller, expectations for a magnetoresistive head (hereinafter, referred to as “MR head”) whose reproduction output does not depend on the speed are increasing. Regarding this MR head, "I
EEE Trans. on Magn,. MAG7 (1
970) 150 ”and“ A Magnetore
Sistity Readout Transdu
cer ".

In recent years, a giant magnetoresistive effect capable of realizing a much higher output with respect to this MR head has attracted attention. In particular, the magnetoresistive effect (generally called a spin valve effect) in which the change in electric resistance corresponds to the cosine between the magnetization directions of two adjacent magnetic layers causes a large change in resistance with a small operating magnetic field. Is expected as an MR head. For an MR head using the spin valve effect, see IEEE Trans. On Magn,.
Vol. 30, no. 6 (1994) 3801 ”in“ Design, Fabrication & Test ”.
ing of Spin-Valve Read Head
ds for High Density Recorder
ding ". Among them, the magnetization of one of the two magnetic layers that generate the spin valve effect is transferred to the head magnetic sensing part by exchange coupling generated by laminating an antiferromagnetic layer on this magnetic layer. It is fixed so that the magnetization direction is substantially aligned with the direction of the entering medium magnetic field. The other magnetic layer adjacent to the fixed magnetic layer via a conductive layer of Cu or the like can freely change the magnetization direction with respect to the medium magnetic field.

In the MR head using the spin valve effect, it is indispensable to make the magnetic layer in which the magnetization changes according to the medium magnetic field into a single magnetic domain in order to suppress Barkhausen noise. As a method of forming the single magnetic domain, “IEEE Trans. On Magn,.
l. 32, no. 1 (1996) 149 "
pin-Valve Heads Utilizing
Antiferromagnetic NiO La
Figures 8 being discussed as “yers”
The structure using the permanent magnet layer shown in (1) has been used. FIG. 10 shows a simplified layer structure of FIG. 8 showing the layer configuration when viewed from the surface facing the medium. That is, the magnetization free layer 111 that changes in response to the medium magnetic field is applied with a longitudinal bias magnetic field by the magnetization of the permanent magnet layers 115 and 116 to be converted into a single magnetic domain. Thus, the antiferromagnetic layer 114, the magnetization fixed layer 113, the conductive layer 11
2. The spin valve laminated film composed of the magnetization free layer 111 is entirely patterned in a region corresponding to the central magnetically sensitive portion, and permanent magnet layers 115 and 116 are arranged at both ends to make the magnetization free layer 111 a single magnetic domain. The method has been taken. The permanent magnet layers 115 and 116 have the electrode layer 11
7, 118 are applied.

In the structure in which the spin-valve laminated film is formed only in the central region as shown in FIG. 10, the spin-valve laminated film is present only in the central region where the magnetic field of the medium is susceptible. As a method of suppressing the generation of noise without any noise, the structure has been inherited from a conventional MR head. This structure is disclosed in Japanese Patent Application Laid-Open No. 3-12531.
No. 1 publication. In a conventional MR head, a soft magnetic layer for biasing an MR layer via a magnetic separation layer is formed in order to realize a linear response of a magnetoresistive layer (hereinafter, referred to as an “MR layer”) to a medium magnetic field. It had been. The soft magnetic layer is magnetized in one direction by a magnetic field caused by a current flowing through the MR layer when a current flows through the three-layer structure including the MR layer, the magnetic separation layer, and the soft magnetic layer. The layers were biased. In the three-layer structure, when a three-layer film exists in an end region other than the center region where the medium magnetic field is detected, the soft magnetic layer is particularly susceptible to an external magnetic field, which causes noise. Was. This is solved by the element structure described in the above-mentioned Japanese Patent Application Laid-Open No. 3-125311. In the spin valve head, of course, low noise characteristics have been realized by the structure disclosed in JP-A-3-125311 in which the spin valve laminated film is formed only in the central region.

[0006]

However, in this structure, not only the magnetization free layer which is originally desired to be a single magnetic domain, but also
The magnetic field of the permanent magnet is also applied to the magnetization fixed layer in which the magnetization must be fixed in the direction perpendicular to the bias magnetic field of the permanent magnet layer by exchange coupling with the antiferromagnetic layer. Despite the exchange coupling with the magnetic layer, it has been clarified that the magnetic field gradually rotates in the direction of the magnetic field generated by the permanent magnet, and as a result, a problem that a normal spin valve operation cannot be performed occurs.
This is a matter which has not been considered in the past because the coercive force of the antiferromagnetic material is as large as several thousand Oersteds or more, and is overwhelmingly larger than the magnetic field generated by the permanent magnet.

[0007]

Therefore, in the MR head according to the present invention, the magnetization of the magnetization fixed layer is gradually changed by the longitudinal bias magnetic field orthogonal to the magnetization of the magnetization fixed layer, and finally the spin valve operation becomes impossible. It is intended to solve the problem.

[0008]

According to the present invention, there is provided a central region formed on a substrate and susceptible to a magnetic field from a medium, and located on both sides of the central region with the central region interposed therebetween. MR using spin valve effect, including an end region having a function of applying a bias and a function of supplying a current
Head. Then, in order to apply a longitudinal bias magnetic field only to the magnetization free layer whose magnetization changes due to the magnetic field from the medium, the magnetization free layer was patterned so as to exist only in the central region, and the magnetization was fixed in the direction of the magnetic field from the medium. A configuration in which the magnetization fixed layer exists in the entire central region and the end region, and a permanent magnet layer for applying a longitudinal bias to the central region is laminated on the end region, and directly connected to an end of the magnetization free layer in the central region. Structure. Alternatively, the magnetization free layer exists over the center region and the end region, the magnetization fixed layer also exists over the center region and the end region, and a permanent magnet layer that applies a longitudinal bias to the center region has a magnetization free layer in the end region. To be directly laminated.

According to the above structure, there is provided a spin valve head structure in which a longitudinal bias magnetic field is not applied to the magnetization fixed layer and a longitudinal bias magnetic field is applied only to the magnetization free layer. In the spin valve head structure described above, the magnetic layer whose magnetization is fixed by exchange coupling with the antiferromagnetic layer in the laminated film constituting the spin valve is not only located in the central region where the medium magnetic field is insensitive, but also in the central region. If there is also an edge region that has a function of applying a vertical bias to the region and a function of supplying current, it is necessary to clarify how much the noise from this edge region effectively affects. Was. Surprisingly, only a small signal of -50 dB or less was detected from the end region of the prototype spin valve head with respect to the center region, and magnetization was fixed to the end region by exchange coupling with an antiferromagnetic layer. Even if there is a magnetic layer
It became clear that there was no problem in practical operation of the head.

[0010] Further, the above structure makes it practical to apply a permanent magnet that can fix the magnetization by its own coercive force as the magnetization fixed layer. That is, as a method of fixing the magnetization, it is possible to apply a conventional laminated film of an antiferromagnetic layer and a magnetic layer and to apply a permanent magnet layer. As a method for realizing the longitudinal bias, a permanent magnet layer and a laminated film of an antiferromagnetic layer and a magnetic layer can be used. Therefore, four methods are possible by multiplying the two. Of these, both the longitudinal bias and the magnetization fixation of the spin valve,
When a laminated film of an antiferromagnetic layer and a magnetic layer is applied, magnetization perpendicular to each other can be fixed by changing the blocking temperature of exchange coupling between the two. In addition, when permanent magnet layers are used, magnetizations perpendicular to each other can be fixed by changing the coercive force of both.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

[0012]

Embodiment 1 An embodiment in which an MR head for a magnetic disk is manufactured will be described with reference to FIG. FIG. 2 shows a layer configuration when the MR head is observed from the surface facing the medium. On a wafer 101 made of an Al ₂ O ₃ —TiO composite ceramic material constituting a slider, a film thickness of 2
A magnetic shield layer 102 made of NiFe having a thickness of 0.08 μm is formed on a magnetic gap layer 103 made of alumina having a thickness of 0.08 μm. The end region 104 having a function of supplying the liquid crystal was formed.

The details of the central region 105 and the end region 104 are as shown in FIG. On the magnetic gap layer 103, an antiferromagnetic layer 4 of NiO having a thickness of 30 nm and a thickness of 3 nm
The magnetization fixed layer 3 made of NiFe was sequentially laminated. At this time, due to exchange coupling between the magnetization fixed layer 3 and the antiferromagnetic layer 4, the magnetization of the magnetization fixed layer 3 is fixed in one direction from the front of the drawing to the back. Since the blocking temperature of exchange coupling between the NiO film and the NiFe film is about 180 ° C., a DC magnetic field is applied in a desired magnetization direction at an intensity of 500 Oe while applying a DC magnetic field.
The magnetization was fixed by heating to 0 ° C. for about 1 minute.

Further, a conductive layer 2 made of Cu having a thickness of 2.5 nm and a magnetization free layer 1 made of NiFe having a thickness of 6 nm
Were sequentially laminated. The magnetization free layer 1 forms a mask using a photoresist, and performs ion beam etching.
The patterning was performed so as to exist only in the central region 105. Using a photoresist mask in which the magnetization free layer 1 is patterned, a 15 nm-thick CoPtC
The permanent magnet layers 5 and 6 made of r, and the electrode layers 7 and 8 made of 150 nm thick Au were formed via the 5 nm thick Ta, and the end region 104 was formed by lift-off. C
Since the coercive force of the oPtCr film is 1 kOe,
The permanent magnet layers 5 and 6 were magnetized in the longitudinal bias direction by a DC magnetic field of k Oersted.

The structure shown in FIG. 1 is hereinafter referred to as "spin valve element". A magnetic gap layer 10 made of alumina having a thickness of 0.1 μm shown in FIG.
6. Magnetic shield layer 10 made of NiFe having a thickness of 3 μm
7 was formed. Further, a recording inductive head (not shown) having the magnetic shield layer 107 as one magnetic pole was laminated. The other magnetic pole 109 made of NiFe was formed via a magnetic gap layer 108 made of alumina having a thickness of 0.35 μm. Between the magnetic shield layer 107 and the magnetic pole 109, a coil (not shown) made of Cu covered with an insulating layer obtained by thermosetting a photoresist.
Was formed. Finally, the entire element was coated with an alumina layer 110, and the electrode terminal of the spin valve element and the electrode terminal of the recording inductive were taken out to complete the wafer process.

At this time, a wafer having a conventional spin valve element shown in FIG. 10 was prepared for comparison. In FIG. 10, the materials and thicknesses of the antiferromagnetic layer 114, the magnetization fixed layer 113, the conductive layer 112, and the magnetization free layer 111 are as shown in FIG.
The same as above. 10, in the step of patterning the magnetization free layer 1 in the central region 105 in FIG. 1, not only the magnetization free layer 11 but also all layers are patterned.

A slider on which each element was mounted was processed from the above wafer, and incorporated into an arm having a gimbal spring, and the recording / reproducing characteristics were evaluated. As a result, FIG.
In the MR head of the spin valve element, the reproduction waveform showed that the magnetization direction of the magnetization fixed layer 113 gradually changed to the direction of the longitudinal bias magnetic field when operated for a long time.
On the other hand, the MR head using the spin valve element shown in FIG. 1 was stable after a long operation. This is because, in the structure of FIG. 1, the longitudinal bias magnetic field from the end region 104 is applied only to the magnetization free layer 1 and is not actually applied to the magnetization fixed layer 3, whereas the conventional structure of FIG. In the element, it can be said that the longitudinal bias magnetic field applied to the magnetization free layer 111 is also applied to the magnetization fixed layer 113.

Further, as a result of evaluating the off-track characteristic of the MR head having the element shown in FIG. 1, it was found that the signal intensity at the time of off-track was sufficiently smaller than -50 dB of that at the time of on-track. It is confirmed that the signal from the end region 104 does not actually cause a problem in the central region 105 even if the structure in which the magnetization fixed layer 3 exists is provided.

[0019]

Example 2 An MR head having the spin valve element shown in FIG. 3 was manufactured. In FIG. 3, the magnetization fixed layer 43 of the spin valve laminated film is formed to a thickness of 10 nm and a coercive force of 200 nm.
CoPtCr of 0 Oersted was magnetized from the front to the back of the drawing as shown in the figure. Furthermore, a film thickness of 2.5 nm
The conductive layer 42 using Cu and the magnetization free layer 41 using NiFe with a film thickness of 5 nm were stacked, and the central region was patterned in the same manner as in Example 1. Furthermore, a 10 nm thick Ni
A longitudinal bias magnetic layer 49 made of Fe, F
Antiferromagnetic layers 45 and 46 made of eMn and a film thickness of 150 n
After sequentially laminating the electrode layers 47 and 48 made of Au of m
An end region was formed by lift-off. FeMn and Ni
Since the blocking temperature of the exchange coupling with Fe is 150 ° C., the element is heated to 160 ° C. while applying a magnetic field of 500 Oersted in a direction assuming a longitudinal bias and not changing the magnetization of the magnetization fixed layer 43, Vertical bias magnetic layer 4
9 by exchange coupling with the antiferromagnetic layers 45 and 46,
Aligned to the longitudinal bias magnetic field direction.

A slider on which each element was mounted was processed from the above wafer, and was assembled into an arm having a gimbal spring, and the recording / reproducing characteristics were evaluated. As a result, it has been found that the MR head using this spin valve element realizes a stable spin valve operation with a long operation. Further, as a result of evaluating the off-track characteristic of the MR head having the element shown in FIG. 3, it was confirmed that the signal intensity during off-track was sufficiently small, -50 dB or less of that during on-track.

[0021]

Embodiment 3 An MR head having a spin valve element shown in FIG. 4 was manufactured. In FIG. 4, the magnetization fixed layer 53 of the spin-valve stacked film was made of CoPtCr having a film thickness of 10 nm and a coercive force of 2 kOe, and was magnetized from the front to the back of the drawing as shown in the figure. Furthermore, a 2.5 nm thick C
A conductive layer 52 using u and a magnetization free layer 51 using NiFe with a thickness of 5 nm are stacked, and the central region is patterned in the same manner as in Example 1. Furthermore, a 15 nm thick CoPt film
Au permanent electrode layers 57 and 58 with a thickness of 150 nm via a permanent magnet layers 55 and 56 made of Cr and Ta with a thickness of 5 nm
Was formed, and an end region was formed by lift-off. Since the coercive force of the permanent magnet layers 55 and 56 is 700 Oersted, the DC magnetic field of 1 k
56 was magnetized in the longitudinal bias direction. At this time, the magnetization of CoPtCr of the magnetization fixed layer 53 does not change effectively because the coercive force is as large as 2 kOersted.

Each of the above wafers is incorporated one by one,
The recording and reproduction characteristics were evaluated. As a result, it has been found that the MR head using this spin valve element realizes a stable spin valve operation with a long operation. Further, as a result of evaluating the off-track characteristics of the MR head having the element shown in FIG. 4, it was confirmed that the signal intensity during off-track was sufficiently small, -50 dB or less of that during on-track.

[0023]

Embodiment 4 An MR head having the configuration of the spin valve element shown in FIG. 5 was manufactured. In FIG. 5, the film thickness is 30n.
m, an antiferromagnetic layer 64 made of NiMn, 3 nm thick N
A magnetization fixed layer 63 made of iFe was laminated. At this time, by the exchange coupling between the magnetization fixed layer 63 and the antiferromagnetic layer 64, the magnetization of the magnetization fixed layer 63 is fixed in one direction from the front of the drawing to the back. Since the blocking temperature of exchange coupling between NiMn and NiFe is about 400 ° C., a DC magnetic field is applied in a desired magnetization direction at a strength of 500 Oe.
Heating was performed at 0 ° C. for 10 hours to fix the magnetization. Further, a conductive layer 62 made of Cu having a thickness of 2.5 nm and N
A magnetization free layer 61 using iFe was laminated, and the central region was patterned in the same manner as in Example 1. Further, a film thickness of 10
nm bias magnetic layer 69 made of NiFe, thickness 1
After sequentially stacking antiferromagnetic layers 65 and 66 made of 5 nm FeMn and electrode layers 67 and 68 made of Au having a thickness of 150 nm, end regions were formed by lift-off. Fe
The blocking temperature of exchange coupling between Mn and NiFe is 15
Since the temperature is 0 ° C., the magnetization fixed layer 63 and the antiferromagnetic layer 6 are placed in a magnetic field of 500 Oe in a direction assuming a longitudinal bias.
By heating to 160 ° C. which does not exceed the blocking temperature of No. 4, the magnetization of the longitudinal bias magnetic layer 69 was aligned in the longitudinal bias magnetic field direction.

A slider on which each element was mounted was processed from the above wafer, and was assembled into an arm having a gimbal spring, and the recording / reproducing characteristics were evaluated. As a result, it has been found that the MR head using this spin valve element realizes a stable spin valve operation with a long operation. Further, as a result of evaluating the off-track characteristics of the MR head having the element shown in FIG. 5, it was confirmed that the signal intensity at the time of off-track was sufficiently small at -50 dB or less of that at the time of on-track.

[0025]

Embodiment 5 An embodiment in which an MR head for a magnetic disk is manufactured will be described with reference to FIG. FIG. 2 shows a layer configuration when the MR head is observed from the surface facing the medium. On a wafer 101 made of an Al ₂ O ₃ —TiO composite ceramic material constituting a slider, a film thickness of 2
A magnetic shield layer 102 made of NiFe having a thickness of 0.08 μm is formed on a magnetic gap layer 103 made of alumina having a thickness of 0.08 μm. The end region 104 having a function of supplying the liquid crystal was formed.

FIG. 6 shows the details of the central region 105 and the end region 104. A 30 nm-thick N layer is formed on the gap layer 103.
An antiferromagnetic layer 14 made of iO and a magnetization fixed layer 13 made of NiFe having a thickness of 3 nm were laminated. At this time, due to exchange coupling between the magnetization fixed layer 13 and the antiferromagnetic layer 14, the magnetization of the magnetization fixed layer 13 is fixed in one direction from the front of the drawing to the back. N
The blocking temperature of the exchange coupling between iO and NiFe is 18
Since the temperature is about 0 ° C., a DC magnetic field is
Heating was performed at 200 ° C. for about 1 minute while applying a voltage of 0 Oe, and the magnetization was fixed. Furthermore, a 2.5 nm thick C
A conductive layer 12 made of u and a magnetization free layer 11 made of NiFe having a thickness of 6 nm were laminated. A mask made of a photoresist is formed on the magnetization free layer 11, and a thickness of 15 nm is formed by a sputtering method using the photoresist mask.
The permanent magnet layers 15 and 16 made of CoPtCr and the electrode layers 17 and 18 made of Au with a thickness of 150 nm were formed via Ta with a thickness of 5 nm, and end regions were formed by lift-off. Since the coercive force of CoPtCr was 1 kOersted, the permanent magnet layers 15 and 16 were magnetized in the longitudinal bias direction with a DC magnetic field of 3 kOersted.

The magnetic gap layer 10 made of alumina having a thickness of 0.1 μm shown in FIG.
6. Magnetic shield layer 10 made of NiFe having a thickness of 3 μm
6 was formed. Further, a recording inductive head (not shown) having the magnetic shield layer 107 as one magnetic pole was laminated. The other magnetic pole 109 made of NiFe was formed via a magnetic gap layer 108 made of alumina having a thickness of 0.35 μm. This magnetic shield layer 10
7 and a magnetic pole 109, a coil (not shown) made of Cu covered with an insulating layer obtained by thermosetting a photoresist was formed. Finally, the entire element was coated with an alumina layer 110, and the electrode terminal of the spin valve element and the electrode terminal of the recording inductive were taken out, and the wafer process was completed.

A slider on which each element was mounted was processed from the above-mentioned wafer and assembled into an arm having a gimbal spring, and the recording / reproducing characteristics were evaluated. As a result, the MR head using the spin valve element shown in FIG. 6 was stable over a long operation. This is because, in the structure of FIG. 2, the longitudinal bias magnetic field from the end region 104 is applied only to the magnetization free layer 11, and
It can be said that this is because the structure does not actually add to the magnetization fixed layer 13. Further, as a result of evaluating the off-track characteristic of the MR head having the element shown in FIG. 6, it was found that the signal intensity during off-track was sufficiently small, -50 dB or less of that during on-track. Layer 1
It was confirmed that the signal from the end region 104 had no practical problem in the central region 105 even in the structure where 3 existed.

[0029]

Embodiment 6 An MR head having a spin valve element shown in FIG. 7 was manufactured. In FIG. 7, the magnetization fixed layer 73 of the spin-valve laminated film was made of CoPtCr having a film thickness of 10 nm and a coercive force of 2 kOe, and was magnetized in the depth direction from the front of the drawing as shown in the figure. Furthermore, a 2.5 nm thick C
A conductive layer 72 using u and a magnetization free layer 71 using NiFe with a thickness of 5 nm were stacked. Further, a vertical bias magnetic layer 79 made of NiFe having a thickness of 10 nm and a thickness of 15 nm
Antiferromagnetic layers 75 and 76 made of FeMn and a film thickness of 15
After sequentially laminating the 0 nm Au electrode layers 77 and 78, an end region was formed by lift-off. Since the blocking temperature of exchange coupling between FeMn and NiFe is 150 ° C., the element is heated to 160 ° C. while applying a magnetic field of 500 Oersted in a direction assuming a longitudinal bias and a magnetic field that does not change the magnetization of the magnetization fixed layer 73. Then, the magnetization of the vertical bias magnetic layer 79 was aligned in the vertical bias magnetic field direction by exchange coupling with the antiferromagnetic layers 75 and 76.

A slider on which each element was mounted was processed from the above wafer, and the slider was mounted on an arm having a gimbal spring, and the recording / reproducing characteristics were evaluated. As a result, it has been found that the MR head using this spin valve element realizes a stable spin valve operation with a long operation. Further, as a result of evaluating the off-track characteristic of the MR head having the element shown in FIG. 7, it was confirmed that the signal intensity at the time of off-track was sufficiently small at -50 dB or less of that at the time of on-track.

[0031]

Embodiment 7 An MR head having a spin valve element having the structure shown in FIG. 8 was manufactured. In FIG. 8, the magnetization fixed layer 83 of the spin-valve laminated film was made of CoPtCr having a film thickness of 10 nm and a coercive force of 2 kOe, and was magnetized from the front to the back of the drawing as shown in the figure. Furthermore, a 2.5 nm thick C
A conductive layer 82 using u and a magnetization free layer 81 using NiFe with a thickness of 5 nm were stacked. Further, 15 nm-thick permanent magnet layers 85 and 86 made of CoPtCr and 5 nm-thick Ta were used to form electrode layers 87 and 88 made of 150 nm-thick Au, and end regions were formed by lift-off. Since the coercive force of the permanent magnet layers 85 and 86 was 700 Oersted, the permanent magnet layers 85 and 86 were magnetized in the bias direction with a DC magnetic field of 1 kOersted. At this time, the magnetization of CoPtCr of the magnetization fixed layer 83 does not change effectively because the coercive force is as large as 2 kOersted.

A slider on which each element was mounted was processed from the wafer described above and assembled into an arm having a gimbal spring, and the recording / reproducing characteristics were evaluated. As a result, it has been found that the MR head using this spin valve element realizes a stable spin valve operation with a long operation. Further, as a result of evaluating the off-track characteristics of the MR head having the element shown in FIG. 8, it was confirmed that the signal intensity at the time of off-track was sufficiently small at -50 dB or less of that at the time of on-track.

[0033]

Embodiment 8 An MR head having a spin valve element having the structure shown in FIG. 9 was manufactured. In FIG. 9, an antiferromagnetic layer 94 made of NiMn having a thickness of 30 nm and NiF having a thickness of 3 nm are formed.
The magnetization fixed layer 93 made of the e layer was laminated. At this time, exchange coupling between the magnetization fixed layer 93 and the antiferromagnetic layer 94 causes
The magnetization fixed layer 93 is fixed in one direction from the front of the drawing to the back. Since the blocking temperature of exchange coupling between NiMn and NiFe is about 400 ° C., 270 ° C. while applying a DC magnetic field in a desired magnetization direction at an intensity of 500 Oe.
For 10 hours to fix the magnetization. Furthermore, a film thickness of 2.5
conductive layer 92 using Cu having a thickness of 5 nm, NiFe having a thickness of 5 nm
The magnetization free layer 61 using was laminated. Further, the film thickness 5
A vertical bias magnetic layer 99 made of NiFe of nm. Film thickness 1
After sequentially stacking antiferromagnetic layers 95 and 96 made of 5 nm FeMn and electrodes 97 and 98 made of 150 nm thick Au, end regions were formed by lift-off. Fe
The exchange coupling blocking temperature between Mn and NiFe is 15
Since the temperature is 0 ° C., the magnetization fixed layer 93 of the spin valve is placed in a magnetic field of 500 Oe in a direction assuming a longitudinal bias.
And 160 not exceeding the blocking temperature of the antiferromagnetic layer 94.
C., and the magnetization of the vertical bias magnetic layer 99 was aligned in the direction of the vertical bias magnetic field.

A slider on which each element was mounted was processed from the above wafer, and was assembled into an arm having a gimbal spring, and the recording / reproducing characteristics were evaluated. As a result, it has been found that the MR head using this spin valve element realizes a stable spin valve operation with a long operation. Further, as a result of evaluating the off-track characteristics of the MR head having the element shown in FIG. 9, it was confirmed that the signal intensity during off-track was sufficiently low, ie, -50 dB or less of that during on-track.

[0035]

According to the MR head of the present invention, it is possible to realize a spin valve head structure in which a longitudinal bias magnetic field is not applied to the magnetization fixed layer and a longitudinal bias magnetic field is applied only to the magnetization free layer. , A stable spin valve operation can be realized. Further, it is possible to substantially prevent the signal intensity from the end region from affecting the signal intensity in the central region.

[Brief description of the drawings]

FIG. 1 is a main part configuration diagram showing a first embodiment of an MR head according to the present invention;

FIG. 2 is a configuration diagram showing an example of the entire MR head according to the present invention.

FIG. 3 is a main part configuration diagram showing a second embodiment of the MR head according to the present invention;

FIG. 4 is a main part configuration diagram showing a third embodiment of the MR head according to the present invention;

FIG. 5 is a main part configuration diagram showing a fourth embodiment of the MR head according to the present invention;

FIG. 6 is a main part configuration diagram showing Embodiment 5 of an MR head according to the present invention.

FIG. 7 is a main part configuration diagram showing a sixth embodiment of the MR head according to the present invention;

FIG. 8 is a main part configuration diagram showing a seventh embodiment of the MR head according to the present invention;

FIG. 9 is a main part configuration diagram showing Embodiment 8 of an MR head according to the present invention.

FIG. 10 is a main part configuration diagram showing a conventional MR head.

[Explanation of symbols]

1, 11, 41, 51, 61, 71, 81, 91 Magnetic free layer 2, 12, 42, 52, 62, 72, 82, 92 Conductive layer 3, 13, 43, 53, 63, 73, 83, 93 Fixed magnetization layer 4, 14, 64, 94 Antiferromagnetic layer (center region side) 5, 6, 15, 16, 55, 56, 85, 86 Permanent magnet layer 7, 8, 17, 18, 47, 48, 57 , 58, 67,
68, 77, 78, 87, 88, 97, 98 Electrode layer 45, 46, 65, 66, 75, 76, 95, 96 Antiferromagnetic layer (end region side) 49, 69, 79, 99 Longitudinal bias magnetism Layer 104 Edge area 105 Central area

Claims (27)

[Claims] 1. A central region having a magnetization free layer whose magnetization direction is changed by a magnetic field from a magnetic recording medium and a magnetization fixed layer whose magnetization direction is fixed, and located at both ends of the central region and in the central region. An end region for supplying a longitudinal bias magnetic field and a current to the magnetoresistive head, which operates by a spin valve effect, wherein the end region supplies the longitudinal bias magnetic field only to the magnetization free layer. A magnetoresistive head. 2. The magnetoresistive head according to claim 1, wherein said longitudinal bias magnetic field is supplied by a permanent magnet layer provided in said end region. 3. The magnetoresistive head according to claim 1, wherein said longitudinal bias magnetic field is supplied by a laminated body of an antiferromagnetic layer and a longitudinal bias magnetic layer provided in said end region. 4. The magnetoresistive head according to claim 1, wherein the magnetization direction of the fixed magnetization layer is fixed by exchange coupling between the fixed magnetization layer and the antiferromagnetic layer. 5. The magnetoresistive head according to claim 1, wherein the magnetization direction of the fixed magnetization layer is fixed by the coercive force of the fixed magnetization layer. 6. The longitudinal bias magnetic field is supplied by a permanent magnet layer provided in the end region, and the magnetization direction of the magnetization fixed layer is fixed by exchange coupling between the magnetization fixed layer and the antiferromagnetic layer. The magnetoresistive head according to claim 1. 7. The longitudinal bias magnetic field is supplied by a laminated body of an antiferromagnetic layer and a longitudinal bias magnetic layer provided in the end region, and magnetization of the fixed magnetization layer is generated by coercive force of the fixed magnetization layer. 2. The magnetoresistive head according to claim 1, wherein the direction is fixed. 8. The longitudinal bias magnetic field is supplied by a permanent magnet layer provided in the end region, and a magnetization direction of the magnetization fixed layer is fixed by a coercive force of the magnetization fixed layer,
2. The magnetoresistive head according to claim 1, wherein the coercive force of the permanent magnet layer is different from the coercive force of the magnetization fixed layer. 9. The vertical bias magnetic field is supplied by a laminated body of a first antiferromagnetic layer and a vertical bias magnetic layer provided in the end region, and the magnetization fixed layer and the second antiferromagnetic layer are supplied. The magnetization direction of the magnetization fixed layer is fixed by exchange coupling with the body layer, and the blocking temperature between the first antiferromagnetic layer and the longitudinal bias magnetic layer, and the magnetization fixed layer and the second 2. The magnetoresistive head according to claim 1, wherein the blocking temperature of exchange coupling with the magnetic layer is different. 10. The magnetoresistive head according to claim 1, wherein the magnetization free layer exists only in the central region, and the magnetization fixed layer exists over the central region and the end region. 11. The magnetoresistive head according to claim 10, wherein said longitudinal bias magnetic field is supplied by a permanent magnet layer provided in said end region. 12. The magnetoresistive head according to claim 10, wherein said longitudinal bias magnetic field is supplied by a laminate of an antiferromagnetic layer and a longitudinal bias magnetic layer provided in said end region. 13. The magnetoresistive head according to claim 10, wherein the magnetization direction of the fixed magnetization layer is fixed by exchange coupling between the fixed magnetization layer and the antiferromagnetic layer. 14. The magnetoresistive head according to claim 10, wherein the magnetization direction of the fixed magnetization layer is fixed by the coercive force of the fixed magnetization layer. 15. The longitudinal bias magnetic field is supplied by a permanent magnet layer provided in the end region, and the magnetization direction of the fixed magnetization layer is fixed by exchange coupling between the fixed magnetization layer and the antiferromagnetic layer. The magnetoresistive head according to claim 10. 16. The longitudinal bias magnetic field is supplied by a laminated body of an antiferromagnetic material layer and a longitudinal bias magnetic layer provided in the end region, and magnetization of the magnetization fixed layer is generated by coercive force of the magnetization fixed layer. 11. The magnetoresistive head according to claim 10, wherein the direction is fixed. 17. The longitudinal bias magnetic field is supplied by a permanent magnet layer provided in the end region, a magnetization direction of the magnetization fixed layer is fixed by a coercive force of the magnetization fixed layer, and the permanent magnet layer is maintained. 11. The magnetoresistive head according to claim 10, wherein a magnetic force is different from a coercive force of the magnetization fixed layer. 18. The longitudinal bias magnetic field is supplied by a laminated body of a first antiferromagnetic layer and a longitudinal bias magnetic layer provided in the end region, and the magnetization fixed layer and the second antiferromagnetic layer are supplied. The magnetization direction of the magnetization fixed layer is fixed by exchange coupling with the body layer, and the blocking temperature between the first antiferromagnetic layer and the longitudinal bias magnetic layer, and the magnetization fixed layer and the second 11. The magnetoresistive head according to claim 10, wherein the blocking temperature of exchange coupling with the magnetic layer is different. 19. The magnetoresistive head according to claim 1, wherein the magnetization free layer exists over the center region and the end region, and the magnetization fixed layer exists over the center region and the end region. 20. The magnetoresistive head according to claim 19, wherein said longitudinal bias magnetic field is supplied by a permanent magnet layer provided in said end region. 21. The magnetoresistive head according to claim 19, wherein said longitudinal bias magnetic field is supplied by a laminated body of an antiferromagnetic material layer and a longitudinal bias magnetic layer provided in said end region. 22. The magnetoresistive head according to claim 19, wherein the magnetization direction of the fixed magnetization layer is fixed by exchange coupling between the fixed magnetization layer and the antiferromagnetic layer. 23. The magnetoresistive head according to claim 19, wherein the magnetization direction of the fixed magnetization layer is fixed by the coercive force of the fixed magnetization layer. 24. The longitudinal bias magnetic field is supplied by a permanent magnet layer provided in the end region, and the magnetization direction of the fixed magnetization layer is fixed by exchange coupling between the fixed magnetization layer and the antiferromagnetic layer. 20. The magnetoresistive head according to claim 19. 25. The vertical bias magnetic field is supplied by a laminated body of an antiferromagnetic layer and a vertical bias magnetic layer provided in the end region, and magnetization of the magnetization fixed layer is generated by coercive force of the magnetization fixed layer. 20. The magnetoresistive head according to claim 19, wherein the direction is fixed. 26. The longitudinal bias magnetic field is supplied by a permanent magnet layer provided in the end region, the magnetization direction of the magnetization fixed layer is fixed by the coercive force of the magnetization fixed layer, and the permanent magnet layer is maintained. 20. The magnetoresistive head according to claim 19, wherein a magnetic force is different from a coercive force of the magnetization fixed layer. 27. The vertical bias magnetic field is supplied by a laminated body of a first antiferromagnetic layer and a vertical bias magnetic layer provided in the end region, and the magnetization fixed layer and the second antiferromagnetic layer are provided. The magnetization direction of the magnetization fixed layer is fixed by exchange coupling with the body layer, and the blocking temperature between the first antiferromagnetic layer and the longitudinal bias magnetic layer, and the magnetization fixed layer and the second 20. The magnetoresistive head according to claim 19, wherein the blocking temperature of exchange coupling with the magnetic layer is different.