JPH0916923A - Magnetoresistive sensor and spin valve sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to impress a sufficiently large longitudinal bias on a spin valve sensor layer and to prevent Barkhausen noises by constituting magnetic domain control layers by successively laminating a ferromagnetic NiFe film and an antiferromagnetic CrMnPt film. SOLUTION: A sensor central region 200 is constituted by successively laminating a soft magnetic film 203, a nonmagnetic film 202 and a magneto-resistance effect film 201. The film 201 is a ferromagnetic film for converting the magnetic signal from a medium to an electric signal by using an anisotropic magneto- resistance effect, for which, for example, the NiFe film is used. The film 203 is a bias film for impressing a transverse bias on the film 201 in order to improve the sensitivity of the film 201 and improving the linearity of a resistance change. An NiFe-ZrO2 film, etc., are used for thin film. The nonmagnetic film 202 is a separating film for magnetically isolating the film 201 and the film 203, for which a Ta film, etc., are used. The magnetic domain control layer 10 is formed by successively laminating the ferromagnetic NiFe film 101 and the anti-ferromagnetic CrMnPt film 102 at both ends of the magneto- resistive sensor layer 200. A magnetic reluctance sensor 1 is formed by forming a pair of signal detecting electrodes 110 above the film 102.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive sensor and a spin valve sensor used in a magnetic disk device.

[0002]

BACKGROUND OF THE INVENTION It is well known to use magnetoresistive sensors utilizing the anisotropic magnetoresistive effect (AMR) to sense magnetically recorded data. It is also known that both longitudinal and lateral bias must be provided to eliminate Barkhausen noise and to keep the sensor within its most linear operating range. One solution proposed to meet the longitudinal bias, which is also the object of the present invention, is Japanese Patent Application No. 7-572.
No. 23. In Japanese Patent Application No. 7-57223, a magnetoresistive sensor layer is arranged only on the central active region of the sensor, and a ferromagnetic film and an antiferromagnetic film are sequentially formed by adjoining both ends of the magnetoresistive sensor layer. A technique for removing Barkhausen noise by applying a longitudinal bias to the magnetoresistive film by using an exchange bias generated between the magnetoresistive film and the antiferromagnetic film to prevent generation of a magnetic domain wall of the magnetoresistive film is disclosed. There is.

Recently, the resistance change of the magnetoresistive sensor has been
A more pronounced magnetoresistive effect has been described, which is attributed to the spin-dependent transmission of conduction electrons between the magnetic layers through the non-magnetic layer and the accompanying spin-dependent scattering at the layer interfaces. This magnetoresistance effect is called by a name such as “giant magnetoresistance effect” or “spin valve effect”. Such a magnetoresistive sensor has improved sensitivity and a larger resistance change than observed with a magnetoresistive sensor utilizing the AMR effect. European Patent EP-490608A2 describes a magnetoresistive sensor utilizing the spin valve effect (hereinafter referred to as a spin valve sensor). The principle of the spin valve sensor will be described below. The spin valve sensor includes a layered structure formed on a suitable material including a first ferromagnetic film and a second ferromagnetic film separated by a non-magnetic film. The magnetization direction of one of the ferromagnetic films, such as the second ferromagnetic film, is fixed perpendicular to the magnetization direction of the first ferromagnetic film when the externally applied magnetic field is zero. The fixed magnetization direction of the second ferromagnetic film is
For example, the antiferromagnetic films are made to be adjacent to each other, and exchange bias between the antiferromagnetic film and the second ferromagnetic film is used. Therefore, the second ferromagnetic film is often named "fixed layer". The typical fixed direction of magnetization is perpendicular to the air bearing surface. On the other hand, the magnetization direction of the first ferromagnetic film can freely rotate according to an externally applied magnetic field, and is often referred to as a "free layer". The magnetization direction of the free layer freely rotates according to the externally applied magnetic field, and the angle between the magnetization direction of the fixed layer and the magnetization direction of the free layer inevitably changes. The spin valve sensor is a magnetoresistive sensor that converts a magnetic signal from a medium into an electrical signal by utilizing the fact that the electrical resistance changes according to the change in the angle of the magnetization direction. In addition, European patent EP-
No. 490608A2 discloses a longitudinal bias applying means which is also an object of the present invention. For example, forming an antiferromagnetic film adjacent to both ends of a spin valve sensor layer disposed on the central active region of the sensor, and generating an antiferromagnetic film / ferromagnetic film exchange bias at both ends of the free layer. Discloses a technique in which a longitudinal bias is applied to the free layer to prevent the generation of domain walls in the free layer, thereby removing Barkhausen noise.

In the antiferromagnetic film as the longitudinal bias applying means, a "coupling magnetic field" generated between the ferromagnetic film and the antiferromagnetic film is defined by the shift amount from the origin of the magnetization curve. However, it is required that the coupling magnetic field is large and that the “blocking temperature” defined by the temperature at which the coupling magnetic field disappears is large. Japanese Patent Application No. 7-57223 and European Patent EP-490608A2 disclose that an antiferromagnetic film satisfying these requirements is a FeMn, NiMn based antiferromagnetic film.

[0005]

In the prior art, a magnetoresistive sensor layer or a spin valve sensor layer is arranged only in the central active region of the sensor, and the magnetic domain control functioning also as electrodes at both ends of the central active region. A layer, that is, an antiferromagnetic film / ferromagnetic film, or a sensor structure in which antiferromagnetic films are adjacently joined is a structure capable of narrowing the track. Further, since the film thickness of each film and each layer can be made extremely thin, it is also a structure capable of narrowing the gap. Furthermore, an exchange bias from the antiferromagnetic film / ferromagnetic film or the antiferromagnetic film that is adjacently joined to both ends of the central active region provides a sufficient longitudinal bias to the magnetoresistive film or the fixed layer. Since it can be applied, it also has a structure capable of preventing generation of a domain wall in the magnetoresistive film or the fixed layer and removing Barkhausen noise.

When the antiferromagnetic film is applied to a magnetoresistive sensor or a spin valve sensor as a magnetic domain control layer,
In addition to exchange coupling characteristics such as coupling magnetic field and blocking temperature, it is necessary to simultaneously satisfy corrosion resistance, electrical conductivity, and ease of preparation.

However, very few antiferromagnetic films disclosed so far can satisfy these requirements at the same time.
For example, Japanese Patent Application No. 7-57223 or European Patent
The antiferromagnetic FeMn / ferromagnetic NiFe film disclosed in EP-490608A2 exhibits a large coupling magnetic field and a blocking temperature, but the antiferromagnetic FeMn film has a problem that its corrosion resistance is extremely low, which makes it difficult to apply. Many. In addition, antiferromagnetic Fe
Attempts have been made to add Cr or the like in order to improve the corrosion resistance of the Mn film, but there is a problem that the coupling magnetic field and the blocking temperature are lowered. Furthermore, antiferromagnetic NiMn /
The ferromagnetic NiFe film has a very large coupling magnetic field and blocking temperature, but has a problem of low corrosion resistance. An antiferromagnetic NiMnCr film which satisfies only the exchange coupling property, corrosion resistance, electric conductivity and easiness of preparation is disclosed in Japanese Patent Application No. 6-76247. Further, it is disclosed that a high temperature heat treatment is necessary in order to secure a large coupling magnetic field and a blocking temperature in the antiferromagnetic NiMnCr / ferromagnetic NiFe film. Therefore, when applying the antiferromagnetic NiMnCr film to the magnetic domain control layer of the spin valve sensor, the pinned layer in the spin valve sensor layer and the magnetic domain control layer have the same magnetization fixed direction due to heat treatment during the manufacturing process. Is inevitable. The antiferromagnetic NiMnCr film is difficult to apply as a domain control layer for spin valve sensors.

The objects of the present invention are: exchange coupling characteristics, corrosion resistance,
An antiferromagnetic film that can satisfy both electrical conductivity and easiness of production is applied to the magnetic domain control layer, and an exchange bias generated between the antiferromagnetic film and the ferromagnetic film causes a magnetoresistive film or a fixed layer to be formed. It is an object of the present invention to provide a magnetoresistive sensor and a spin valve sensor for high-density recording provided with Barkhausen noise removing means and further provided with means for narrowing a track and narrowing a gap.

[0009]

The above-mentioned object is to form a magnetoresistive sensor layer or a spin valve sensor layer only in the central active region of the sensor, and electrically connect the following magnetic domain control layers to both ends of the central active region. This can be achieved by forming them by adjoining while maintaining continuity.

The magnetic domain control layer is a magnetic domain control layer in which an antiferromagnetic film CrMnPt film is formed on a ferromagnetic NiFe film, or a ferromagnetic NiFe film is formed on a Ta film, and the antiferromagnetic Cr film is formed thereon.
The magnetic domain control layer has an MnPt film formed thereon, or the magnetic domain control layer has an antiferromagnetic CrMnPt film formed on a ferromagnetic film having a bcc structure.

These laminated films may be continuously formed in vacuum at room temperature while applying a magnetic field of a certain magnitude, using a technique such as a sputtering method.

When the composition of the antiferromagnetic CrMnPt film is expressed as Cr _a Mn _b Pt _c , a is 30 to 70 at.% And b is 30 to 70 a.
t,% and c are 3.0 to 30.0 at.%, and a, b, c
Is 100.

[0013]

Since the magnetoresistive sensor layer or the spin valve sensor layer of the present invention is formed only in the central active region, it is easy to narrow the track of the sensor. Further, since each film and each layer of the sensor are formed to have an extremely thin film thickness, it is easy to narrow the gap.

Conventionally, it has been considered that the CrMn-based antiferromagnetic film has the bcc crystal structure and does not exchange-couple with the ferromagnetic NiFe film having the fcc crystal structure. U.S. Pat. No. 4,103,315 even states that antiferromagnetic CrMn films are useless. However, the inventors have found that Pt is added to the antiferromagnetic CrMn film to form exchange coupling by forming it on the ferromagnetic NiFe film or on the ferromagnetic film having the bcc crystal structure. Moreover, the coupling magnetic field between them and the blocking temperature were large.

Therefore, by forming the magnetic domain control layer of the present invention at both ends of the central active region, a longitudinal bias can be applied to the magnetoresistive sensor layer or the spin valve sensor layer formed in the central active region. Magnetoresistive film,
Alternatively, it is possible to prevent generation of domain walls in the fixed layer and remove Barkhausen noise.

Further, since the antiferromagnetic CrMnPt film has a large Cr content, it has an effect of remarkably improving the corrosion resistance.

Further, since the antiferromagnetic CrMnPt film is a metal, it has excellent electric conductivity and also functions as an electrode of the magnetoresistive sensor layer or the spin valve sensor layer.

Further, since a high coupling magnetic field and a blocking temperature are exhibited only when formed at room temperature, a high temperature heat treatment step is unnecessary, and not only is it easy to apply as a magnetic domain control layer of a spin valve sensor, but also easy to manufacture. There is an action that can be done.

Therefore, by forming the magnetic domain control layer of the present invention by adjoining both ends of the sensor central active region, Barkhausen noise can be suppressed and corrosion resistance is excellent.
It is possible to provide a magnetoresistive sensor and a spin valve sensor for high-density magnetic recording that are easy to manufacture.

[0020]

Embodiments of the present invention will be described below.

First, a method of manufacturing the magnetic domain control layer of the present invention will be described. FIG. 2 is an explanatory diagram showing a film structure of a typical magnetic domain control layer 10. The magnetic domain control layer 10 is formed by using a technique such as a sputtering method at room temperature at the ferromagnetic NiFe film 10
1. The antiferromagnetic CrMnPt film 102 was continuously formed in vacuum.
In addition, when the film was sputtered, a magnetic field of a certain magnitude was applied to the film. By applying a magnetic field, the magnetic moment of the ferromagnetic NiFe film 101 first faces the direction of the applied magnetic field, and then the magnetic field of the antiferromagnetic CrMnPt film 102 is aligned with the internal magnetic field of the ferromagnetic NiFe film 101. As a result, unidirectional anisotropy (exchange bias) can be applied to the ferromagnetic NiFe film 101.

FIG. 3 shows ferromagnetic NiFe / antiferromagnetic CrMnPt2.
It is a magnetization curve of a layer film. Here, the ferromagnetic NiFe film 10
The thickness of 1 is about 40 nm. The magnetization curve of the two-layer film is
It is completely unidirectionally shifted, and the unidirectional anisotropy is given to the ferromagnetic NiFe film. Further, the coupling magnetic field is about 20 Oe from the shift amount. Figure 4 shows ferromagnetic NiFe /
This is the temperature dependence of the coupling magnetic field of the antiferromagnetic CrMnPt bilayer film.
The temperature at which the coupling magnetic field of the two-layer film disappears, that is, the blocking temperature is about 370 ° C., which is a very large value. These coupling magnetic field and blocking temperature are as large as possible for the antiferromagnetic CrMnPt film to function as the magnetic domain control layer of the magnetoresistive sensor layer or the spin valve sensor layer.

The antiferromagnetic CrMnPt film of the present invention had a bcc crystal structure. The ferromagnetic NiFe film has a fcc crystal structure as is well known. Antiferromagnetic CrMnPt
Even though the film has a bcc crystal structure, fcc
It was confirmed that the film was epitaxially grown on the NiFe film having the crystal structure of. More specifically, a large coupling magnetic field and blocking temperature were observed when the (110) plane of the CrMnPt film was epitaxially grown on the (111) plane of the NiFe film. When the laminated structure was reversed, it was not possible to obtain a coupling magnetic field.

FIG. 5 shows the result of a corrosion resistance test in a so-called lapping liquid, which is used during sensor processing of the antiferromagnetic CrMnPt film of the present invention. For comparison, the results of antiferromagnetic NiMn system are also shown. Corrosion current density of antiferromagnetic CrMnPt film is 10 ^-4
A / m ^2, which is 10 ^-2 A / m ^{2 of the} antiferromagnetic NiMn film.
It is extremely superior to

Further, by improving the corrosion resistance, the corrosion current density of the antiferromagnetic NiMnCr film containing Cr is 10 ⁻³ A /
It was about m ² . Thus, the antiferromagnetic CrMnPt film is
Since it is a Cr-based material, it has overwhelmingly superior corrosion resistance compared to other antiferromagnetic films.

FIG. 1 is an enlarged cross-sectional view of the magnetoresistive sensor 1 according to the first embodiment of the present invention as seen from the air bearing surface. The sensor central region 200 is composed of a layer in which a soft magnetic film 203, a non-magnetic film 202, and a magnetoresistive effect film 201 are sequentially stacked. The magnetoresistive film 201 is a ferromagnetic film that converts a magnetic signal from the medium into an electrical signal by using the anisotropic magnetoresistive effect, and is a NiFe film here. The soft magnetic film 203 is a bias film for applying a lateral bias to the magnetoresistive effect film 201 in order to improve the sensitivity of the magnetoresistive effect film 201 and improve the linearity of resistance change.
It is a NiFe-ZrO ₂ film. The non-magnetic film 202 is a separation film for magnetically isolating the magnetoresistive film 201 and the soft magnetic film 203, and is a Ta film here. The magnetoresistive film 201, the soft magnetic film 203, and the nonmagnetic film 202 have thicknesses of 15 to 30 nm, 15 to 30 nm, and 2 respectively.
３０30 nm. The magnetic domain control layer 10 of the present invention is formed by adjoining both ends of the magnetoresistive sensor layer 200 while maintaining electrical continuity.
The CrMnPt films 102 are sequentially laminated and formed. Then, a pair of signal detection electrodes 110 is formed above the antiferromagnetic CrMnPt film 102.
To complete the formation of the magnetoresistive sensor 1.

Exchange bias is applied to the ferromagnetic NiFe film 101 by exchange coupling between the ferromagnetic NiFe film 101 and the antiferromagnetic CrMnPt film 102 formed at both ends of the central active region. Since this exchange bias is large, it enters the magnetoresistive effect film 201 formed in the central active region as a longitudinal bias. Therefore, it is possible to prevent the generation of the domain wall of the magnetoresistive effect film 201 and remove the Barkhausen noise.

FIG. 6 is a sectional view of the magnetoresistive sensor 2 according to the second embodiment of the present invention as seen from the air bearing surface. Magnetoresistive sensor layer 2
The configuration and materials of No. 00 are the same as those in the first embodiment, and the description thereof will be omitted. In the second embodiment, the magnetic domain control layer 20 is formed by adjoining both ends of the magnetoresistive sensor layer 200 while maintaining electrical continuity. The magnetic domain control layer 20 includes the Ta film 103,
The ferromagnetic NiFe film 101 and the antiferromagnetic CrMnPt film 102 are
It is formed by sequentially stacking in a vacuum. Then antiferromagnetic CrMn
The pair of signal detection electrodes 110 is formed above the Pt film 102 to complete the formation of the magnetoresistive sensor 2.

It was confirmed that the (111) plane orientation of the NiFe film was improved by using the Ta film as a base film of the ferromagnetic NiFe film, and the orientation of the (110) plane of the CrMnPt film formed thereon was confirmed. It was also confirmed that it improved. Therefore, by using the Ta film as the base film, the coupling magnetic field between the ferromagnetic NiFe film 101 and the antiferromagnetic CrMnPt film 102 can be improved.

Therefore, a larger exchange bias than that of the magnetic domain control layer 10 can be applied to the ferromagnetic NiFe film 101 of the magnetic domain control layer 20 formed at both ends of the central active region. This exchange bias enters the magnetoresistive effect film 201 formed in the central active region as a larger longitudinal bias. Therefore, the magnetoresistive effect film 2
It is possible to prevent the generation of the domain wall of No. 01 and remove Barkhausen noise.

FIG. 7 is an enlarged sectional view of the magnetoresistive sensor 3 according to the third embodiment of the present invention as seen from the air bearing surface. The structure, material, etc. of the magnetoresistive sensor layer 200 are the same as those in the first embodiment, and the description thereof is omitted. In Example 3, the following magnetic domain control layer 30 is formed by adjoining both ends of the magnetoresistive sensor layer 200 while maintaining electrical continuity. The magnetic domain control layer 30 is bcc
The ferromagnetic film 104 having the crystal structure of 1 and the antiferromagnetic CrMnPt film 102 are sequentially formed in vacuum by stacking. After that, a pair of signal detection electrodes 11 is formed above the antiferromagnetic CrMnPt film 102.
0 is formed to complete the formation of the magnetoresistive sensor 3.

Since the ferromagnetic film 104 has a bcc crystal structure, when a CrMnPt film having the same bcc crystal structure is formed above the CrMnPt film, Cr is formed on the (110) plane of the ferromagnetic film 104.
It was confirmed that the (110) plane of the MnPt film was epitaxially grown. Also, thereby, the coupling magnetic field between them can be improved.

Therefore, the ferromagnetic film 10 having the bcc crystal structure of the magnetic domain control layer 30 formed at both ends of the central active region.
An exchange bias larger than that of the magnetic domain control layer 10 can be applied to the magnetic field control layer 4. This exchange bias enters the magnetoresistive effect film 201 formed in the central active region as a larger longitudinal bias. Therefore, it is possible to prevent the generation of the domain wall of the magnetoresistive effect film 201 and remove the Barkhausen noise.

FIG. 8 is an enlarged sectional view as seen from the air bearing surface of the spin valve sensor 4 according to the fourth embodiment of the present invention. The central region of the sensor includes a base film 301 and a first ferromagnetic film (free layer) 30.
2, a nonmagnetic film 303, a second ferromagnetic film 304 (fixed layer), and an antiferromagnetic film 305 are sequentially stacked. The antiferromagnetic film 305 is a layer for applying an exchange bias to the fixed layer 304, and is a NiMnCr film having relatively good corrosion resistance here. The magnetic moment in the fixed layer 304 is aligned in the direction perpendicular to the air bearing surface by the exchange bias from the antiferromagnetic film 305. Here, NiFe is used.
It was a membrane. The nonmagnetic layer 303 includes the fixed layer 304 and the free layer 3.
02 is a film which is magnetically separated from each other, and is a Cu film here. The magnetic moment of the free layer 302 is a film that can freely rotate according to a magnetic signal from the medium, and is a NiFe film. The base film 301 is a film that controls the orientation of the unevenness and the film formed above it, and is a Ta film here. The thickness of the antiferromagnetic film 305 is
5 to 20 nm, the thickness of the base film 301 is 2 to 10 nm, the thickness of the free layer 302 is 3 to 10 nm, and the thicknesses of the nonmagnetic layer 303 and the fixed layer 304 are 1.5 to 5 nm. The magnetic domain control layer 10 of the present invention is provided on both ends of the spin valve sensor layer 300,
The ferromagnetic film NiFe film 101 and the antiferromagnetic CrMnPt film 102 are sequentially formed by sequentially adjoining while maintaining electrical continuity. After that, the pair of signal detection electrodes 110 is formed above the antiferromagnetic CrMnPt film 102 to complete the formation of the spin valve sensor 4.

Exchange bias is applied to the ferromagnetic NiFe film 101 by exchange coupling between the ferromagnetic NiFe film 101 and the antiferromagnetic CrMnPt film 102 formed at both ends of the central active region. Since this exchange bias is large, it enters the free layer 302 formed in the central active region as a longitudinal bias. Therefore, it is possible to prevent the generation of the domain wall of the free layer 302 and remove the Barkhausen noise.

FIG. 9 is an enlarged sectional view of the spin valve sensor 5 according to the fifth embodiment of the present invention as seen from the air bearing surface. The structure, material, and the like of the spin valve sensor layer 300 are the same as those in the fourth embodiment, and the description will be omitted. In the fifth embodiment, the magnetic domain control layer 20 is formed by adjoining both ends of the spin valve sensor layer 300 while maintaining electrical continuity. Magnetic domain control layer 20
Is Ta film 103, ferromagnetic NiFe film 101, antiferromagnetism
The CrMnPt film 102 is formed by sequentially stacking in a vacuum. Then, a pair of signal detection electrodes 110 are formed above the antiferromagnetic CrMnPt film 102 to complete the formation of the spin valve sensor 5.

It was confirmed that the (111) plane orientation of the NiFe film was improved by using the Ta film as the base film of the ferromagnetic NiFe film, and the orientation of the (110) plane of the CrMnPt film formed thereon was confirmed. It was also confirmed that it improved. Therefore, by using the Ta film as the base film, the coupling magnetic field between the ferromagnetic NiFe film and the antiferromagnetic CrMnPt film can be improved.

Therefore, a larger exchange bias than that of the magnetic domain control layer 10 can be applied to the ferromagnetic NiFe film 101 of the magnetic domain control layer 20 formed on both ends of the central active region. This exchange bias enters the free layer 302 formed in the central active region as a larger longitudinal bias. Therefore, it is possible to prevent the generation of the domain wall of the free layer 302 and remove the Barkhausen noise.

FIG. 10 is an enlarged sectional view of the spin valve sensor 6 according to the sixth embodiment of the present invention as seen from the air bearing surface. The structure, material, and the like of the spin valve sensor layer 300 are the same as those in the fourth embodiment, and the description will be omitted. In Example 6, the magnetic domain control layer 30
Are formed by adjoining both ends of the spin valve sensor layer 300 while maintaining electrical continuity. Magnetic domain control layer 30
Is a ferromagnetic film 104 having a bcc crystal structure, antiferromagnetic
The CrMnPt film 102 is formed by sequentially stacking in a vacuum. After that, the pair of signal detection electrodes 110 is formed above the antiferromagnetic CrMnPt film 102 to complete the formation of the spin valve sensor 6.

Since the ferromagnetic film 104 has a bcc crystal structure, when a CrMnPt film having the same bcc crystal structure is formed above the CrMnPt film, Cr is formed on the (110) plane of the ferromagnetic film 104.
It was confirmed that the (110) plane of the MnPt film was epitaxially grown. Also, thereby, the coupling magnetic field between them can be improved.

Therefore, the ferromagnetic film 10 having the bcc crystal structure of the magnetic domain control layer 30 formed at both ends of the central active region.
An exchange bias larger than that of the magnetic domain control layer 10 can be applied to the magnetic field control layer 4. This exchange bias enters the free layer 302 formed in the central active region as a larger longitudinal bias. Therefore, the free layer 30
It is possible to prevent the generation of domain wall 2 and remove Barkhausen noise.

When the composition of the antiferromagnetic CrMnPt film 102 of the present invention is expressed as Cr _a Mn _b Pt _c , a is 30 to 70 at.
%, B is 30 to 70 at.%, C is 3.0 to 30.0 at.
%, And the total of a, b, and c is 100. Further, when expressed as Cr _a Mn _b M _c , M is Cu, Au, Co,
Similar effects can be expected with one or more metal elements selected from the group consisting of Ni and platinum.

The composition of the ferromagnetic film 101 of the present invention is Ni _a
When represented as Fe _b , a is 75 to 85 at.%,
b is 15 to 25 at.%, and the sum of a and b is 100.
It is.

Since the antiferromagnetic CrMnPt film 102 of the present invention is a metal film, it has excellent electrical conductivity. Furthermore, since a large coupling magnetic field and a blocking temperature can be obtained at room temperature, it is easy to prepare. Further, since the magnetoresistive sensor layer and the spin valve sensor layer are formed only in the central active region, it is possible to narrow the track. Further, the films forming the magnetoresistive sensor layer and the spin valve sensor layer, and the film thicknesses of the respective layers are very thin, and the gap can be narrowed.

Therefore, by arranging the magnetoresistive sensor layer or the spin valve sensor layer in the central active region and forming the magnetic domain control layers of the present invention at both ends thereof, Barkhausen noise can be suppressed, high corrosion resistance, and easy to prepare. It is possible to provide a magnetoresistive sensor and a spin valve sensor that can simultaneously satisfy the characteristics, narrow track, and narrow gap.

Further, in the first, second, third, and fourth embodiments, the magnetoresistive sensor in which the soft magnetic film 203, the nonmagnetic film 202, and the magnetoresistive effect film 201 are laminated in reverse order may be used.

Furthermore, in Examples 5, 6, 7 and 8, the free layer 3 is used.
02, non-magnetic layer 303, fixed layer 304, antiferromagnetic film 305
A spin valve sensor in which the stacking order is reversed may be used.

Furthermore, in Examples 5, 6, 7 and 8, the base film 3 was used.
01 may be an Hf film, a Zr film, or a NiO film.

Further, the magnetic domain control layers 10, 20,
The same effect can be expected when 30 is applied to a so-called double spin valve sensor.

[0050]

The coupling magnetic field and blocking temperature between the ferromagnetic NiFe film and the antiferromagnetic CrMnPt film are large, and the magnetic domain control layers formed by sequentially stacking these are formed at both ends of the central active region. Allows a sufficiently large longitudinal bias to be applied to the magnetoresistive sensor layer or the spin valve sensor layer formed in the central active region, preventing the domain wall of the magnetoresistive film or the fixed layer from being generated, and It is possible to prevent Hausen noise. Furthermore, since the antiferromagnetic CrMnPt film contains a large amount of Cr, the corrosion resistance can be significantly improved. Furthermore, since the antiferromagnetic CrMnPt film is a metal, it has excellent electrical conductivity and can also serve as an electrode of the sensor. Furthermore, since it exhibits good exchange coupling characteristics only when formed at room temperature, a high temperature heat treatment step is unnecessary and the fabrication is easy. Further, since the sensor layer is formed only in the central active region, it is easy to narrow the track. Further, since each film and each layer of the sensor are composed of extremely thin films, it is possible to narrow the gap.

Therefore, by forming the magnetic domain control layer of the present invention by adjoining both ends of the sensor central active region, Barkhausen noise can be prevented and excellent corrosion resistance can be obtained.
It is possible to provide a magnetoresistive sensor and a spin valve sensor for high-density magnetic recording that can be easily manufactured and have a narrow track and a narrow gap.

[Brief description of the drawings]

FIG. 1 is a sectional view of a magnetoresistive sensor showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a magnetic domain control layer of the present invention.

FIG. 3 is a magnetization characteristic diagram of a typical CrMnPt / NiFe laminated film of the present invention.

FIG. 4 is an explanatory diagram of temperature dependence of a coupling magnetic field of a typical CrMnPt / NiFe laminated film of the present invention.

FIG. 5 is an explanatory diagram of results of a corrosion resistance test of the CrMnPt film of the present invention.

FIG. 6 is a sectional view of a magnetoresistive sensor according to a second embodiment of the present invention.

FIG. 7 is a sectional view of a magnetoresistive sensor showing a third embodiment of the present invention.

FIG. 8 is a sectional view of a spin valve sensor showing a fourth embodiment of the present invention.

FIG. 9 is a sectional view of a spin valve sensor showing a fifth embodiment of the present invention.

FIG. 10 is a sectional view of a spin valve sensor showing a sixth embodiment of the present invention.

[Explanation of symbols]

10 ... Magnetic domain control layer, 101 ... Ferromagnetic NiFe film, 102
... Antiferromagnetic CrMnPt film, 110 ... Signal detection electrode, 200 ...
Magnetoresistive sensor layer, 201 ... Magnetoresistive effect film, 202 ...
Non-magnetic film, 203 ... Soft magnetic film.

Claims (6)

[Claims] 1. A magnetoresistive sensor layer including a magnetoresistive effect film for converting a magnetic signal into an electrical signal by using an anisotropic magnetoresistive effect is formed only in a sensor central active region, and both ends of the central active region are formed. In a magnetoresistive sensor including a magnetic domain control layer formed by adjoining the magnetic resistance sensor layer while maintaining electrical continuity with the magnetoresistive sensor layer, the magnetic domain control layer sequentially stacks a ferromagnetic NiFe film and an antiferromagnetic CrMnPt film. A magnetoresistive sensor characterized by being configured as follows. 2. A magnetoresistive sensor layer including a magnetoresistive effect film for converting a magnetic signal into an electric signal by using an anisotropic magnetoresistive effect is formed only in a sensor central active region, and both ends of the central active region are formed. In a magnetoresistive sensor including a magnetic domain control layer formed by adjoining a magnetic domain sensor layer while maintaining electrical continuity with the magnetoresistive sensor layer, the magnetic domain control layer comprises a Ta film, a ferromagnetic NiFe film, and an antiferromagnetic layer.
A magnetoresistive sensor characterized by being formed by sequentially stacking CrMnPt films. 3. A magnetoresistive sensor layer including a magnetoresistive effect film for converting a magnetic signal into an electrical signal by using an anisotropic magnetoresistive effect is formed only in a sensor central active region, and both ends of the central active region are formed. In a magnetoresistive sensor including a magnetic domain control layer formed by adjoining the magnetic resistance sensor layer while maintaining electrical continuity with the magnetoresistive sensor layer, the magnetic domain control layer is a ferromagnetic film having a bcc crystal structure, or an antiferromagnetic layer. A magnetoresistive sensor characterized by being formed by sequentially stacking CrMnPt films. 4. A spin valve sensor layer including a first ferromagnetic film, a non-magnetic film, a second ferromagnetic film, and an antiferromagnetic film is formed only in the sensor central active region, and both ends of the central active region are formed. In a magnetoresistive sensor including a magnetic domain control layer formed by adjoining while maintaining electrical continuity with the spin valve sensor layer, the magnetic domain control layer sequentially stacks a ferromagnetic NiFe film and an antiferromagnetic CrMnPt film. A spin valve sensor characterized by being configured as follows. 5. A spin valve sensor layer including a first ferromagnetic film, a non-magnetic film, a second ferromagnetic film, and an antiferromagnetic film is formed only in the sensor central active region, and both ends of the central active region are formed. In a spin valve sensor including a magnetic domain control layer formed by adjoining the spin valve sensor layer while maintaining electrical continuity with the spin valve sensor layer, the magnetic domain control layer comprises a Ta film, a ferromagnetic NiFe film, and an antiferromagnetic layer.
A spin valve sensor characterized by being formed by sequentially stacking CrMnPt films. 6. A spin valve sensor layer including a first ferromagnetic film, a non-magnetic film, a second ferromagnetic film, and an antiferromagnetic film is formed only in the sensor central active region, and both ends of the central active region are formed. In a spin valve sensor including a magnetic domain control layer formed by adjoining while maintaining electrical continuity with the spin valve sensor layer, the magnetic domain control layer is a ferromagnetic film having a bcc crystal structure, or an antiferromagnetic CrMnPt. A spin valve sensor characterized by being formed by sequentially stacking films.