JPH10320721A - Magnetoresistive head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magneto-resistance effect head utilizing a yoke, highly sensitive and suitable for running in contact with a medium/head. SOLUTION: This magneto-resistance effect head is provided with the magnetic yokes 111, 112 to regulate a magnetic gap 12 for leading a signal magnetic field from a recording medium on the surface confronted with the recording medium, huge magneto-resistance effect elements 131, 132 magnetically coupled with the magnetic yokes 111, 112 at the positions away from the surface confronted with the recording medium, and means 141, 142 for supplying a sense current in the direction perpendicular to film surfaces of the huge magneto-resistance effect elements 131, 132.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a yoke type magnetoresistive head.

[0002]

2. Description of the Related Art In a magnetic recording apparatus such as a hard disk drive (HDD), an ultra-high density recording of 10 G bits or more per square inch has become a target. In order to improve the recording density, the recording track width of the recording medium must be narrowed to increase the track density, and the linear recording density in the recording track direction must be improved. Reading from a medium with a narrow track width requires a highly sensitive reproducing head.
For this reason, a magnetic head utilizing the giant magnetoresistive effect, which can obtain a much higher rate of change in resistance than the conventional magnetic head utilizing the anisotropic magnetoresistive effect, is promising. Further, in reading from a recording medium having a high linear recording density, it is important to reduce the gap between the head and the recording medium and also reduce the reproduction gap length so that a contact operation or a pseudo contact operation can be performed.

Conventionally, there is known a shield type MR head having a structure in which a magnetoresistive element (MR element) is arranged on a surface (ABS surface) of a head substrate facing a recording medium and magnetic shields are provided on both sides thereof. I have. But MR
Since the element is supplied with a sense current, the element becomes electrically unstable when it comes into contact with the medium, and in the worst case, the head is electrically destroyed. Further, due to the heat generated by contact with the medium, the temperature of the MR element may rise and the head operation may become unstable. Further, in the structure in which the MR elements are arranged between the magnetic shields, it is difficult to reduce the gap.

[0004] For the purpose of solving these problems, a yoke type MR head has been proposed (for example, IEEE Trans.
Magn., Vol. MAG-26 (1990) 2406). The yoke type MR head has a magnetic yoke formed so as to define a magnetic gap on the ABS surface of the head substrate, and two MR elements formed electrically insulated from the magnetic yoke. M
A sense current flows through the R element along its film surface. In such a structure, since the magnetic yoke and the MR element are insulated, even if the magnetic yoke contacts the recording medium, there is no adverse effect on the MR element. Further, since there is no need to provide an MR element or an electrode in the magnetic gap defined by the magnetic yoke, it is relatively easy to reduce the gap.

On the other hand, in this structure, the MR element is
Retreating from the BS surface greatly reduces the reproduction sensitivity. Therefore, in order to obtain sufficient reproduction sensitivity, it is necessary to bring the MR element as close to the medium as possible. However, when a GMR element made of a metal laminated film such as a spin valve is arranged close to a medium, it is extremely difficult to secure electrical insulation from a magnetic yoke and to form electrodes.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a yoke type magnetoresistive head which has high sensitivity and is suitable for medium / head contact operation.

[0007]

According to the present invention, there is provided a magnetoresistive head comprising: a magnetic yoke defining a magnetic gap for guiding a signal magnetic field from a recording medium at a surface facing a recording medium; Giant magnetoresistive element (GMR element) magnetically coupled to the magnetic yoke at
And means for supplying a sense current in a direction perpendicular to the film surface of the giant magnetoresistive element.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

In the present invention, the magnetic yoke for defining the magnetic gap for guiding the signal magnetic field from the recording medium on the surface facing the recording medium may be formed of a single-layer magnetic film. In this case, as the magnetic film, NiFe; an amorphous film such as CoZrNb; a microcrystalline film such as FeTaN or FeHfC;
A soft magnetic film such as AlSi can be used. However, the magnetic yoke has a thickness of 0.01 to 0.5 μm and a thickness of 1 to 50 nm made of Ta, Cr, AlN or the like.
And a non-magnetic layer are alternately laminated to have a laminated structure including at least two magnetic layers. The magnetic yoke having such a laminated structure can easily control magnetic domains and can effectively suppress Barkhausen noise.

In the present invention, the GMR element has a magnetic field detection layer (or region) and a magnetization fixed layer (or region), and utilizes a resistance change based on spin-dependent scattering. Specifically, it is preferable to use a GMR element having the following structure. An example of a suitable GMR element is a ferromagnetic layer (magnetic field detection layer or free layer) having a thickness of 1 to 200 nm and a thickness of 1 to 2 made of an insulator or a semiconductor.
Non-magnetic layer with high resistance of 50 nm and ferromagnetic layer with fixed magnetization of 1 to 200 nm in thickness (pinned layer or pinned layer)
And a laminated structure. Another example of a suitable GMR element has a granular magnetic film in which magnetic particles made of Co, Fe, Ni or an alloy thereof are dispersed in a high-resistance nonmagnetic matrix made of a semiconductor or an insulator. In the granular magnetic film, a region near one surface is a magnetic field detection region, and a region near the other surface is a magnetization fixed region.

In order to fix the magnetization of the ferromagnetic layer (pin layer), a structure in which antiferromagnetic layers such as Ir ₂₂ Mn ₇₈ , CrMn, and NiMn are stacked is adopted. Specific examples of such a laminated configuration include Fe / Al ₂ O ₃ / Fe / IrMn,
Co / Al ₂ O ₃ / Co / IrMn, Co / CoO / C
o / IrMn, Co ₉₀ Fe ₁₀ / Al ₂ O ₃ / Co ₉₀ Fe
₁₀ / IrMn and Fe / Si / Fe / CrMn. Note that a hard magnetic film such as CoPt may be used as the pinned layer, and the antiferromagnetic layer may be omitted.

The GMR element having the above structure has a high resistance. In the present invention, since the sense current is supplied in a direction perpendicular to the film surface of the GMR element, a relatively large resistance can be obtained by using a high-resistance GMR element, and a large reproduction output can be expected.

On the other hand, as a GMR element, an element in which a ferromagnetic layer (free layer), a metal non-magnetic layer, and a ferromagnetic layer (pinned layer) are laminated, such as a spin valve, is also known. However, in a GMR element in which all layers are made of metal, when a sense current flows in a direction perpendicular to the film surface, the resistance is significantly reduced. Therefore, only a very small reproduction output can be obtained even if the resistance change rate is large.

In a GMR element having a structure in which a free layer, a high-resistance nonmagnetic layer and a pinned layer are laminated, a free layer may be provided directly on a magnetic yoke and exchange-coupled, or an insulating layer may be sandwiched on a magnetic yoke. Alternatively, a free layer may be provided for magnetostatic coupling. The magnetic yoke may have a function as a free layer by forming a high resistance nonmagnetic layer and a pin layer on the magnetic yoke. The magnetization direction of the pin layer is preferably fixed at a position where the magnetic yoke is magnetically coupled to the GMR element so as to be substantially parallel or anti-parallel to the direction of the signal magnetic field flowing into the magnetic yoke. In this GMR element, when the magnetization of the magnetic yoke is rotated by the signal magnetic field, the magnetization of the free layer also rotates in the direction of the magnetization of the magnetic yoke. As a result, the angle formed by the magnetization of the free layer and the pinned layer changes in accordance with the change in the magnetization direction of the magnetic yoke, causing a resistance change accompanying spin-dependent scattering.

In a GMR element having a granular magnetic film, for example, a granular magnetic film is provided on a magnetic yoke and is magnetically coupled to form a magnetization fixed film (pin layer) and an antiferromagnetic layer on the granular magnetic film. The magnetization of the magnetic particles in the region (the magnetization fixed region) of the granular magnetic film in the vicinity of the pinned layer is generally oriented in the direction of magnetization of the pinned layer by exchange coupling. On the other hand, magnetic particles in a region (magnetic field detection region) near the magnetic yoke of the granular magnetic film cause exchange coupling with the magnetic yoke. In this GMR element, when the magnetization of the magnetic yoke rotates due to the signal magnetic field, the magnetization of the magnetic particles in the granular magnetic film near the magnetic yoke also rotates in the direction of the magnetization of the magnetic yoke. As a result, in accordance with the change in the magnetization direction of the magnetic yoke, the angle formed by the magnetization between the adjacent magnetic particles along the thickness direction of the granular magnetic film changes, and a resistance change accompanying spin-dependent scattering occurs.

In the present invention, an electrode is provided on the GMR element, and a sense current is supplied in a direction perpendicular to the film surface of the GMR element, and further flows through a magnetic yoke. In such a configuration, since the magnetic yoke can be set to the ground potential, stable reproduction can be realized even when the magnetic yoke contacts the medium.

The magnetoresistive head of the present invention may have either a structure in which the thickness direction of the magnetic yoke substantially matches the track direction or a structure in which the thickness direction of the magnetic yoke substantially matches the track width direction.

The MR head in which the thickness direction of the magnetic yoke substantially coincides with the track direction has more specifically the following structure. At the center of the head, a thickness of 0.01
A GMR element magnetically coupled to the magnetic yoke is formed on a magnetic yoke of about 0.1 μm at a position away from the medium facing surface. This central magnetic yoke and G
Two magnetic gap films are formed above and below the MR element. Further, a thickness of 0.5 mm above and below the magnetic gap film.
Two magnetic yokes of ３3 μm are formed. actually,
On the head substrate, along the track direction, the outer magnetic yoke film, the magnetic gap film, the center magnetic yoke film, the GMR
The element, the magnetic gap film, and the outer magnetic yoke film are stacked. The two outer magnetic yokes enclose the central magnetic yoke where the GMR elements are magnetically coupled, and also function as a magnetic shield against external noise magnetic fields. As described above, the magnetic yoke coupled to the GMR element is preferably thinner than the outer magnetic yoke. If the magnetic yoke at the center is made thinner, the signal magnetic flux density inside the magnetic yoke becomes higher, the magnetization rotation of the GMR element coupled to this magnetic yoke can be effectively caused, and high-sensitivity reproduction can be realized. Further, since the magnetic yokes are provided above and below the magnetic gap film, the gap can be easily narrowed by reducing the thickness of the magnetic gap film.

In an MR head in which the thickness direction of the magnetic yoke substantially coincides with the track width direction, two sides are located on the left and right of the magnetic gap.
The two magnetic yokes are arranged in a plane. In this structure,
Since the thickness of the magnetic yoke can be made smaller than the reproduction track width, an MR head corresponding to a narrow track width can be easily formed.

In the present invention, two sets of GMR elements are used, and two GMR elements are used at two positions where the directions of the signal magnetic fields flowing into the magnetic yoke are opposite to each other.
Preferably, the element is magnetically coupled to the magnetic yoke.

The case where the magnetization directions of the pinned layers (pinned layers) of the two sets of GMR elements are opposite to each other will be described. In this configuration, when signal magnetic fields in opposite directions are applied to the two sets of GMR elements, a change in resistance is superimposed, and a large reproduction output is obtained. On the other hand, two sets of GM
When a noise magnetic field in the same direction is applied to the R element from the outside, the resistance change is canceled out and the noise magnetic field is not detected. Therefore, good reproduction of the S / N ratio becomes possible.

The case where the magnetization directions of the pinned layers (pin layers) of the two sets of GMR elements are the same will be described. In this case, a differential amplifier is provided at the output terminals of the two GMR elements, and only the sign of the output of one GMR element is inverted, and the output is added to the output of the other GMR element. Also in this configuration, when signal magnetic fields in opposite directions are applied to the two sets of GMR elements, a change in resistance is superimposed by the differential amplifier circuit, and a large reproduction output is obtained. On the other hand, when a noise magnetic field in the same direction is externally applied to the two sets of GMR elements, the resistance change is canceled by the differential amplifier circuit, and the noise magnetic field is not detected. Therefore, good reproduction of the S / N ratio becomes possible.

[0023]

Embodiments of the present invention will be described below.

Embodiment 1 FIG. 1 is a perspective view of a magnetoresistive head according to this embodiment as viewed from the ABS side. In this MR head, the thickness direction of the magnetic yoke substantially coincides with the track width direction.

A pair of front yokes 1 is provided on the main surface of the substrate 10.
11 and 112 are formed so as to define the magnetic gap 12. These front yokes 111, 112
Are the ferromagnetic layer 113, the nonmagnetic layer 114, and the ferromagnetic layer 1
It has a laminated structure consisting of 15 layers. With such a laminated structure, an increase in the demagnetizing field can be suppressed even when the front yoke is miniaturized, and magnetic domains are hardly generated in the front yoke, so that Barkhausen noise can be suppressed. Ferromagnetic layers 113 and 115 constituting front yokes 111 and 112
As shown by arrows in FIG. 1, magnetic anisotropy is imparted substantially along the recording track direction (x direction in the figure) of the recording medium. When such magnetic anisotropy is introduced, the medium magnetic field can be efficiently introduced into the front yoke. The thickness (y direction) of the front yokes 111 and 112 is adjusted to a recording track width on the order of submicron or less. GMR elements 131 and 132 magnetically coupled to the respective front yokes 111 and 112 are formed at positions retracted from the ABS.
These GMR elements 131 and 132 are composed of a free layer 133 / nonmagnetic layer 134 / pinned layer 135 / protective film (FIG. 1).
Are omitted). At a position further away from the ABS than the GMR elements 131 and 132, the thick rear yoke 1 is in contact with and magnetically couples to the upper surfaces of both front yokes 111 and 112.
5 are formed. By increasing the thickness of the rear yoke 15, the efficiency of the magnetic circuit can be improved. On the GMR elements 131 and 132, electrodes 141 and 142 for supplying a sense current are formed. An electrode terminal is also formed on the rear yoke 15, and this electrode terminal is grounded. When the rear yoke 15 is grounded, the front yoke 11
1 and 112 are also almost at the ground potential. Although not shown, the magnetic pole of the recording unit is formed by lamination on the reproducing unit. Note that a recording coil may be applied to the rear yoke 15 to form a recording / reproducing integrated magnetic head.

In this magnetoresistive head, the sense current I flows from each electrode to the ground electrode terminal via the GMR element, the front yoke, and the rear yoke (see the broken line in FIG. 1). Thus, the sense current is supplied in a direction perpendicular to the film surfaces of the GMR elements 131 and 132. With such a configuration, the front yoke 11
The GMR elements 1 and 112 can be set to the ground potential, so that even if the front yoke comes into contact with the medium, the GMR element will not be destroyed electrically.

In the magneto-resistance effect head, reproduction is performed according to the following principle. The medium magnetic field Hs introduced from the gap 12 is approximately 18 degrees apart from each other at the respective front yokes 111 and 112, as shown by the broken lines in FIG.
0 ° in the opposite direction. Correspondingly, two sets of GMR
The magnetizations of the pinned layers 135 of the elements 131 and 132 are mutually 180 degrees along the direction of the medium magnetic field (z direction in the drawing) at the respective positions of the front yokes 111 and 112.
° It is fixed in the opposite direction. The free layer 133 of the two sets of GMR elements 131 and 132 is the front yoke 1
The magnetization directions of the front yokes 111 and 112 and the free layer 133 are substantially the same. Then, the front yoke 1 is caused by the medium magnetic field.
When the magnetizations of 11 and 112 rotate, the magnetization of the free layer 133 also rotates in accordance with the rotation. As a result, the pinned layer 1
35 and the free layer 133 change the angle formed by the magnetization and G
The resistance of the MR elements 131 and 132 changes, and a signal is detected.

In the magnetoresistive head shown in FIG.
Since the MR element is used, a large reproduction output can be obtained as described below. That is, when the medium magnetic field flows into the front yokes 111 and 112, the magnetizations of the front yokes 111 and 112 rotate in directions opposite to each other at the position where the respective GMR elements are stacked.
The magnetization of the pinned layer 135 of each GMR element is
They are oriented 180 ° opposite each other. Therefore, the resistance change with respect to the medium magnetic field increases (or decreases) in any of the GMR elements. Therefore, since a resistance change is superimposed, a large reproduction output can be obtained. On the other hand, both front yokes 1
The magnetizations of 11, 11 rotate in the same direction. However, the magnetizations of the pinned layers 135 of each GMR element are oriented 180 ° opposite each other. Therefore, the resistance change increases in one GMR element and decreases in the other GMR element with respect to the noise magnetic field. Therefore, no noise magnetic field is detected in total.

Hereinafter, a method of manufacturing the magnetoresistive head shown in FIG. 1 will be described.

The front yoke and the gap film are formed as follows. First, a ferromagnetic layer, a non-magnetic layer, and a ferromagnetic layer forming the front yoke are formed. At this time, induced magnetic anisotropy is introduced into the ferromagnetic layer by film formation in a magnetic field. As the ferromagnetic layer, a NiFe alloy, CoZrN
A Co-based amorphous such as a b alloy or a nitride film such as FeTaN is used. This laminated film is etched into a predetermined shape by a method such as ion milling, reactive ion etching (RIE), and focused ion beam (FIB) to form a front yoke. Next, an insulator such as SiOx is formed by a directional method such as collimation sputtering and buried between the front yokes to form a gap film. SiOx is also deposited in a region other than the gap. Then, by etch back or polishing,
The gap film and the front yoke are flattened to a predetermined thickness equal to or less than the track width. By such a method, a yoke corresponding to a narrow track width can be easily formed.

The gap film may be formed by sputtering or the like, the region where the front yoke is formed by RIE or the like may be removed and processed. The front yoke may be formed into a predetermined shape, and then flattened. In addition, one front yoke is formed and processed into a predetermined shape, a gap film is formed and processed into a predetermined shape, and the remaining front yoke is formed and processed into a predetermined shape. May go. However, in the latter method, the gap surface is slightly inclined with respect to the track width direction.

The GMR element is formed by sequentially forming a free layer, a non-magnetic layer, a pinned layer, and a protective film by sputtering or the like, and then etching into a predetermined shape by a method such as ion milling. As the free layer and the pinned layer, Co, Ni, Fe alone or an alloy containing these as main components is used. For example, CoFe, NiFe, F
e, NiFeCo, CoNi, Co and the like.
As the nonmagnetic layer, a semiconductor such as Si, an insulator such as Al ₂ O ₃ , or an oxide of a magnetic material constituting a free layer or a pinned layer is used. Ta, Ti, N
b, Mo, etc. are used. Note that the front yoke is G
If used as the free layer of the MR element, it is not necessary to form the free layer independently.

The rear yoke is preferably formed by a method such as lift-off or plating. This is because if the rear yoke is processed by, for example, ion milling, the GMR element may be damaged by over-etching. For the rear yoke, Ni
A soft magnetic film such as an Fe alloy, an amorphous alloy, or a microcrystalline film containing Fe or Co as a main component and containing nitrogen, carbon, and oxygen is used.

An electrode for supplying a sense current to the GMR element and a ground electrode terminal connected to the rear yoke are formed as follows. First, an insulating layer such as SiOx is formed so as to cover the GRM element and the rear yoke. A contact hole is formed in a terminal portion of the insulating layer on the GMR element and on the rear yoke. Next, T
An electrode material such as a / Cu / Ta is sputtered to bury the electrode inside the contact hole. The electrode material is processed into a predetermined shape by a method such as ion milling to form an electrode. The rear yoke may be formed before forming the GMR element.

In the above, the case where the GMR element is formed on each of the pair of front yokes has been described. However, the GMR element may be formed only on one of the front yokes. In this case, it is necessary to magnetically shield the GMR / yoke portion in order to prevent the inflow of a noise magnetic field from the outside. A part of this magnetic shield may be used also as a magnetic pole of a recording unit laminated on the reproducing unit.

Embodiment 2 In Embodiment 1 (FIG. 1), two sets of GMR elements 131,
Although the directions of magnetization of the pin layers of 132 are set to be substantially opposite to each other, the directions of magnetization of the pin layers of the GMR elements 131 and 132 may be set to be substantially the same. In this case, as shown in FIG. 2, two sets of GMR elements 131 and 13 are provided.
2 is provided with a differential amplifier 16 at the output end to invert only the sign of the output of one GMR element 132 and
It is added to the output of the MR element 131.

As described in the first embodiment, the medium magnetic field Hs
Flows into the front yokes 111 and 112, the magnetizations of the front yokes 111 and 112 rotate in opposite directions at the positions where the respective GMR elements are stacked. Here, when the magnetizations of the pinned layers 135 of the respective GMR elements 131 and 132 are oriented in the same direction, the increase or decrease of the resistance change in each GMR element is opposite to each other. At this time, one GM
If only the sign of the output of the R element 132 is inverted and added to the output of the other GMR element 131, the resistance change is superimposed, and a large reproduction output is obtained. On the other hand, since a change in resistance in the two sets of GMR elements can be offset with respect to an external noise magnetic field, the noise magnetic field is not detected. Therefore, reproduction with a high output and a good S / N ratio can be achieved.

Embodiment 3 FIG. 3 is a sectional view of a magnetoresistive head according to this embodiment. This figure shows a cross section along a track direction (x direction) and a direction perpendicular to the medium surface (z direction). In this magnetoresistive head, the thickness direction of the magnetic yoke and the track direction substantially match.

The substrate 10 is made of NiFe, amorphous CoZrN
A first magnetic yoke 211 made of b or the like is formed. A part of the first magnetic yoke 211 is removed by etching and the insulator 22 is embedded. Magnetic yoke 2
11 on the ABS side and on the insulator 22
a, made of a nonmagnetic conductor such as Cr, having a thickness of 0.01 to
A lower magnetic gap film 212 of 0.1 μm is formed. Lower magnetic gap film 212 and magnetic yoke 211
The thickness of 0.01-0.
A second magnetic yoke 213 of 2 μm is formed. Since the first and second magnetic yokes 211 and 213 are in direct contact with the portion receded from the ABS in this manner,
The efficiency of the magnetic circuit can be improved. Second magnetic yoke 213
A GMR element 23 is formed above (a position corresponding to above the insulator 22). GMR element 23
Is a laminate of a non-magnetic layer 232, a pinned layer 233, and a protective film 234 made of a free layer 231 / a high-resistance semiconductor or insulator. Since the lower magnetic gap film 212 and the insulator 22 are provided below the second magnetic yoke 213 in contact with the GMR element 23 as described above,
The medium magnetic field can be effectively introduced into the GMR element. An electrode 24 is formed on the GMR element 23. An upper magnetic gap film 214 having a thickness of 0.01 to 0.1 μm is formed so as to cover a part of the GMR element 23, the electrode 24, and a portion of the second magnetic yoke 213 receded from the ABS. The upper magnetic gap film 214 must be a magnetic and electrical insulator near the GMR element, but may be a conductor near the ABS. Further, a third magnetic yoke 215 is formed so as to cover a part of the upper magnetic gap film 214 and the second magnetic yoke 213 that are recessed from the ABS. Although not shown, a recording unit is formed on the reproducing unit by lamination.

In this magnetoresistive head, a sense current is supplied from the electrode 24 in a direction perpendicular to the film surface of the GMR element 23, and flows to the second magnetic yoke 213 set to the ground potential. Therefore, even if the head contacts the medium, stable reproduction can be realized. Also in this magnetoresistive head, the signal magnetic flux sucked from the magnetic yoke 213 flows into the magnetic circuit formed by the magnetic yokes 211 and 215, and the GM that contacts the magnetic yoke 213
The data is efficiently propagated to the free layer 231 of the R element and reproduction is performed. Further, as described above, by reducing the thickness of the lower magnetic gap film 212, the second magnetic yoke 213, and the upper magnetic gap film 214, a narrow gap can be easily formed.

It should be noted that also in FIG.
Is used as the free layer of the GMR element, it is not necessary to form the free layer independently.

Fourth Embodiment A modification of the first and second embodiments in which the configuration of the GMR element is changed will be described with reference to FIGS. 4 (A) and 4 (B). 4A and 4B show a magnetic yoke and a granular GMR element formed thereon.

The GMR element 31 shown in FIG. 4 has a granular magnetic film 32 having a thickness of 1 to 100 nm and a thickness of 1 to 2 nm.
A ferromagnetic layer (pin layer) 33 having a fixed magnetization of 0 nm, an antiferromagnetic layer 34 having a thickness of 3 to 50 nm, and a thickness of 1 to 50
It has a structure in which a protective film (not shown) of nm is laminated. The GMR element 31 is laminated on the magnetic yoke 35 so as to be magnetically coupled. Note that a ferromagnetic layer may be inserted to stabilize the magnetic coupling between the granular magnetic film 32 and the magnetic yoke 35. The above-described granular magnetic film 32 is obtained by dispersing magnetic particles 322 having an average particle diameter of 20 nm or less in a non-magnetic matrix 321. The non-magnetic matrix 321 is made of a semiconductor or an insulator. The magnetic particles 322 are made of a simple substance of Co, Fe, Ni or an alloy thereof. The pin layer 33 is made of Co, Fe, C
oFe, NiFe, NiFeCo and the like. The antiferromagnetic layer 34 is made of IrMn, FeMn, CrMn, or the like. The magnetization of the pin layer 33 is fixed by the antiferromagnetic film 34. Note that a hard magnetic film such as CoPt may be used as the pinned layer 33 and the antiferromagnetic layer 34 may be omitted. The protection film (not shown) is made of a conductive film such as Ta, Zr, and Ti.

The magnetic particles constituting the granular magnetic film may be paramagnetic when the external magnetic field is substantially zero, but the magnetic particles are dispersed in a non-magnetic matrix so that weak exchange coupling acts between the magnetic particles. It is desirable to be magnetic. Such a granular magnetic film can be formed by simultaneously sputtering two targets of a non-magnetic matrix and magnetic particles. Preferred granular magnetic films include Co / Al-O. Pin layer 33
Is preferably magnetized in a direction substantially perpendicular to the magnetization direction of the magnetic yoke 35 when no signal magnetic field is flowing (in a direction substantially parallel or anti-parallel to the signal magnetic field flowing into the magnetic yoke).

The magnetization of the magnetic particles in the granular magnetic film 32 in the region near the magnetic yoke 35 (magnetic field detection region) tends to be aligned in the same direction as the magnetization of the magnetic yoke 35. The magnetization of the magnetic particles in the granular magnetic film 32 in the region (the magnetization fixed region) near the magnetization fixed layer 33 is likely to be aligned in the same direction as the magnetization direction of the magnetization fixed layer 33. As a result, when the signal magnetic field is substantially zero, the magnetization of the magnetic particles in the granular magnetic film 32 near the magnetic yoke 35 and the magnetization of the magnetic particles in the granular magnetic film 32 near the magnetization fixed layer 33 are substantially orthogonal.

In this state, the signal magnetic field Hs is applied to the magnetic yoke 35.
Near the pin layer 33 and the magnetic yoke 3 when
Consider the magnetization directions of magnetic particles in the granular magnetic film 32 in two regions near 5. As shown in FIG. 4A, when a signal magnetic field (called a positive signal magnetic field) in the same direction as the magnetization direction of the pinned layer 33 flows into the magnetic yoke 35, the magnetization directions of the two regions become parallel. Conversely, as shown in FIG. 4B, when a signal magnetic field (referred to as a negative signal magnetic field) in the opposite direction to the magnetization direction of the pinned layer 33 flows into the magnetic yoke 35, the magnetization directions of the two regions become antiparallel. Become. As a result, a linear response is obtained according to the signal magnetic field, and a reproduced signal with less distortion and an excellent SN ratio is obtained.

Embodiment 5 FIGS. 5A and 5B show another embodiment of the present invention. As shown in FIG. 5A, two sets of magnetic yokes 411 for defining a magnetic gap on the medium facing surface are provided on the substrate 10.
412 are formed such that the thickness direction coincides with the track width direction. The magnetic yokes 411 and 412 are magnetically coupled to the GMR element 43 at a position away from the medium facing surface to form a magnetic circuit.

FIG. 5B shows details of the GMR element 43 and the magnetic yoke. FIG. 5 (B) is 5B- of FIG. 5 (A).
5 shows a cross section along line 5B. A magnetic insulator 42 such as Ta is embedded between the magnetic yokes 411 and 412 to form a magnetic gap. On top of these, the free layer 43
1, nonmagnetic layer 432, pinned layer 433, antiferromagnetic layer 434
Is formed.

The free layer 431 is formed so as to be in contact with the magnetic yokes 411 and 412 across the magnetic insulator 42. On the free layer 432, a non-magnetic layer 432 is formed. An insulating layer 44 is provided on the non-magnetic layer 432, and a portion corresponding to the magnetic gap is etched to form a groove. The pin layer 433 is embedded in the groove formed in the insulating layer 44 and has a width substantially equal to the magnetic gap. An antiferromagnetic layer 434 is formed on the pin layer 433.
Are formed. Antiferromagnetic layer 434 and insulating layer 44
An electrode 45 is formed thereon. Magnetic yokes 411, 4
Reference numeral 12 functions as the other electrode and is set to the ground potential. The sense current flows from the electrode 45 in a direction perpendicular to the film surface of the GMR element 43 and flows to the magnetic yokes 411 and 412 at the ground potential. In order to reduce the resistance of the electrode portion of the GMR element 43, the magnetic insulator 42 is preferably made of a metal having a small electric resistance.

The free layer 431 has an easy axis of magnetization in the z direction. When the signal magnetic field is zero, the magnetization of the free layer 431 is oriented in the z direction. The magnetization of the pin layer 433 is
It is fixed in the track direction (x direction in the figure) by the antiferromagnetic film 434. This direction is parallel or anti-parallel to the direction in which the signal magnetic field flows into the free layer 431 of the GMR element through the magnetic yokes 411, 412. Therefore, when a signal magnetic field in the same direction as the direction of magnetization of the pinned layer 433 is applied, the resistance of the GMR element decreases. Conversely, when a signal magnetic field in the opposite direction to the magnetization of the pinned layer 433 is applied, the resistance of the GMR element increases. As a result, the signal magnetic field can be reproduced.

In FIG. 5B, the magnetic yokes 411, 41
The free layer 431 is formed directly on the substrate 2, and they are exchange-coupled. However, the two layers may be magnetostatically coupled to each other with an electrical insulating layer interposed therebetween, and an electrode may be connected to the free layer 431 to be set to the ground potential. In this case, since a sense current does not flow through the magnetic yokes 411 and 412, an extremely stable contact operation can be performed.

[0052]

As described in detail above, according to the present invention, it is possible to provide a yoke-type magnetoresistive head having high sensitivity and suitable for medium / head contact running.

[Brief description of the drawings]

FIG. 1 is a perspective view of a magnetoresistive head according to a first embodiment.

FIG. 2 is a diagram illustrating a detection circuit including a differential amplifier in the magnetoresistive head according to the second embodiment.

FIG. 3 is a sectional view of a magnetoresistive head according to a third embodiment.

FIG. 4 is a diagram showing the direction of magnetization of a granular magnetic film when a signal magnetic field is directed in one direction and in a reverse direction in the magnetoresistive effect head of Example 4.

FIG. 5 is a perspective view and a sectional view of a magnetoresistive effect head according to a fifth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Substrate 111, 112 ... Front yoke 12 ... Magnetic gap 113 ... Ferromagnetic layer 114 ... Nonmagnetic layer 115 ... Ferromagnetic layer 131, 132 ... GMR element 133 ... Free layer 134 ... Nonmagnetic layer 135 ... Pinned layer 141, 142 ... Electrode 15 ... Rear yoke 16 ... Differential amplifier 211 ... First magnetic yoke 22 ... Insulator 212 ... Lower magnetic gap 213 ... Second magnetic yoke 23 ... GMR element 231 ... Free layer 232 ... Non-magnetic layer 233 ... Pin layer 234: protective film 24: electrode 215: third magnetic yoke 31: GMR element 32: granular magnetic film 33: magnetization fixed film 34: antiferromagnetic film 35: magnetic yoke 411, 412: magnetic yoke 42: magnetic gap 43: GMR element 431: free layer 432: non-magnetic layer 433: pin Layer 434: Antiferromagnetic layer 44: Insulating layer 45: Electrode

Claims (7)

[Claims] A magnetic yoke defining a magnetic gap for guiding a signal magnetic field from a recording medium at a surface facing the recording medium; and a giant magnetoresistance magnetically coupled to the magnetic yoke at a position distant from the surface facing the recording medium. A magnetoresistive head comprising: an effect element; and means for supplying a sense current in a direction perpendicular to a film surface of the giant magnetoresistive element. 2. The magnetoresistive head according to claim 1, wherein the giant magnetoresistive element has a granular magnetic film having a structure in which magnetic particles are dispersed in a nonmagnetic matrix. 3. The magnetoresistive head according to claim 1, wherein the giant magnetoresistive film has a laminated structure of a magnetic field detecting layer, a nonmagnetic layer, and a pinned layer. 4. A giant magnetoresistive element having two sets, the giant magnetoresistive elements being magnetically coupled to the magnetic yoke at two positions where the directions of signal magnetic fields introduced into the magnetic yoke are different from each other. 2. The magnetoresistive head according to claim 1, wherein the head is coupled. 5. The magnetoresistive head according to claim 4, wherein the directions of the fixed magnetization in the two sets of giant magnetoresistive elements are substantially opposite to each other. 6. The magnetoresistive head according to claim 4, wherein the directions of the fixed magnetization in the two sets of giant magnetoresistive elements are substantially in the same direction. 7. The magnetoresistive head according to claim 1, wherein a sense current flows from the giant magnetoresistive element through the magnetic yoke, and the magnetic yoke is set to a ground potential.