JP2000216454A - Magnetic resistance effect element and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic resistance element superior in the sensitivity of a magnetic resistance change and to provide the manufacture, by fixing the direction of the magnetic moment of deposited magnetic particles in one granular layer to one direction, and changing the direction of the magnetic moment of the deposited magnetic particles in the other granular layer in accordance with an outer magnetic field. SOLUTION: A magnetic resistance effect element 1 has an anti-ferromagnetic layer 2, plural granular layers 6 containing magnetic particles 8 and a non- magnetic layer 5. In the magnetic resistance effect element 1, one granular layer 6 in plural granular layers 6 is a pinning layer 3 where the direction of the magnetic moment of the deposited magnetic particles is fixed to one direction by the anti-ferromagnetic layer 2, and the other granular layer 6 is a free layer 5 where the direction of the magnetic member of the deposited magnetic particles 7 changes in accordance with the outer magnetic field H.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-resistance effect element constituting a magnetic head used for a hard disk or the like and a method of manufacturing the same. More particularly, the invention relates to a multi-layer magneto-resistance effect element having a plurality of granular layers. The present invention relates to a magnetoresistive element in which the direction of a magnetic moment of a granular layer is fixed in one direction, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Hitherto, as a magnetoresistive element, a spin valve giant magnetoresistive (hereinafter referred to as spin valve GMR) element comprising an antiferromagnetic layer, a pinning layer, a nonmagnetic layer, and a free layer has been disclosed in Japanese Patent Application Laid-Open No. Hei 9 (1999). -266334. In this spin valve GMR element, the manifestation of the magnetoresistance effect occurs in the nonmagnetic layer provided between the pinning layer and the free layer.

Further, a magneto-resistance effect element in which magnetic particles such as an Ag—FeCo-based granular material precipitate in a conductive phase and a magnetic moment becomes parallel from a random state due to an external magnetic field and changes in magneto-resistance is disclosed in Japanese Unexamined Patent Publication No. No. 254510.

Further, JP-A-9-63823 discloses a magnetoresistive element in which low coercive force magnetic particles and high coercive force magnetic particles are simultaneously precipitated in a conductive phase and a bias is applied to a change in magnetoresistance with respect to an external magnetic field. I have.

Furthermore, Japanese Patent Application Laid-Open No. 9-289345 discloses a magnetoresistive element in which a granular layer is formed into a multilayer and a magnetoresistance is obtained by utilizing a difference in coercive force.

[0006]

However, in the above-described spin valve GMR element, a very thin nonmagnetic layer of 20 to 30 ° provided between the pinning layer and the free layer produces a magnetoresistance effect. , The magnetoresistance (hereinafter referred to as MR) ratio is usually less than 10%,
There is a limit. In addition, in order to actually operate as a magnetic head, it is necessary to take measures against Barkhausen noise in the free layer and to perform vertical bias processing for linearly operating the pinning layer so that the magnetic anisotropy is orthogonal to the free layer. There is a problem that the interface of the laminated film is sometimes disturbed by heat and the operation becomes unstable.

Further, in a magnetoresistive element in which the magnetic moment is changed from a random state to a parallel state by an external magnetic field, the magnetic moment of the precipitated particles is changed from a random state to a parallel state by an external magnetic field. There is also a problem that a lateral bias must be added to detect the polarity of the external magnetic field.

Further, there is another problem that low coercive force magnetic particles and high coercive force magnetic particles having contradictory magnetic properties must be precipitated in the same phase and magnetic coupling must be prevented.

Further, in a magnetoresistive effect element in which a granular layer is multilayered and a magnetoresistance is obtained by utilizing a difference in coercive force, it is necessary to form a granular layer having a large difference in coercive force and a large MR magnetic field sensitivity. Have difficulty. In addition, since the magnetic moment of the high coercive force magnetic particles is shifted by an external magnetic field, there is a problem that it is difficult to obtain an efficient resistance change.

The present invention has been made in view of such a problem, and the direction of the magnetic moment of the precipitated magnetic particles of one of the plurality of granular layers is fixed in one direction by an antiferromagnetic layer. It is another object of the present invention to provide a magnetoresistive element having excellent sensitivity to magnetoresistive change by changing the direction of the magnetic moment of the deposited magnetic particles of the other granular layer according to an external magnetic field, and a method for manufacturing the same. I do.

[0011]

According to the present invention, there is provided a magnetoresistance effect element having an antiferromagnetic layer, a plurality of granular layers containing magnetic particles, and a nonmagnetic layer. One of the granular layers is a pinning layer in which the direction of the magnetic moment of the precipitated magnetic particles is fixed in one direction by an antiferromagnetic layer, and the other granular layer is the direction of the magnetic moment of the precipitated magnetic particles. Is a free layer that changes according to an external magnetic field.

In the present invention, a nonmagnetic layer is interposed between the pinning layer and the free layer to prevent magnetic exchange coupling.

The method of manufacturing a magnetoresistive element according to the present invention comprises the steps of laminating an antiferromagnetic layer, a first granular layer containing magnetic particles, a nonmagnetic layer and a second granular layer containing magnetic particles in this order. The antiferromagnetic layer, the first granular layer,
The nonmagnetic layer and the second granular layer are heat-treated in a magnetic field to precipitate magnetic particles contained in the first and second granular layers, and to form a regular lattice in the antiferromagnetic layer. Magnetic exchange coupling with the magnetic layer, and fixing the magnetic moment of the magnetic particles of the first granular layer in the direction of the magnetic field.

In the present invention, since the direction of the magnetic moment of the magnetic particles is fixed by the antiferromagnetic layer,
The polarity of the pinning layer is unlikely to be inverted due to the fluctuation of the external magnetic field, and the direction of the magnetic moment of the magnetic particles of the pinning layer is unlikely to fluctuate stably within the operating magnetic field.

Further, in the present invention, while the magnetization moment of the pinning layer is fixed in a certain direction,
When the magnetic moment of the magnetic particles in the free layer changes according to the external magnetic field, the magnetic moment becomes parallel or antiparallel to the magnetic moment in the pinning layer, and a large change in magnetoresistance can be obtained.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a magnetoresistive element according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 is a perspective view showing a magnetoresistive element according to a first embodiment of the present invention.

In the magnetoresistive element 1 of this embodiment,
On the antiferromagnetic layer 2, a pinning layer 3, a nonmagnetic layer 4, and a free layer 5 are sequentially laminated. In each of the pinning layer 3 and the free layer 5, precipitated magnetic particles 7 are non-solid-solution deposited in the matrix. In the pinning layer 3, the precipitated magnetic particles 7 are all fixed in a fixed direction, and in the free layer 5, the precipitated particles 7 are not fixed in a fixed direction.

Next, the composition of each layer of the magnetoresistive element 1 will be described. The antiferromagnetic layer 2 is made of, for example, FeMn,
It is formed of NiMn, PtMn, NiO, or the like. The pinning layer 3 is made of, for example, Ag or AgCu
The system alloy and the precipitated magnetic particles 7 are made of a CoFe alloy. The nonmagnetic layer 4 is made of, for example, Ag or an AgCu-based alloy.
The free layer 5 has, for example, an Ag or AgCu-based alloy in the matrix and a CoFe alloy in the precipitated magnetic particles 7.

Next, the behavior of the deposited magnetic particles 7 in the pinning layer 3 and the free layer 5 in the magnetoresistive element 1 based on the above configuration will be described. FIG. 2 is a graph showing a magnetization curve with magnetization on the vertical axis and magnetic field on the horizontal axis. FIG.
Is the magnetic resistance ratio (MR ratio) on the vertical axis and the magnetic field on the horizontal axis.
FIG. 4 is a graph showing a change in magnetoresistance with respect to an external magnetic field.
FIGS. 4A to 4D are cross-sectional views showing the behavior of the magnetoresistive element due to an applied external magnetic field.

A current was applied to the magnetoresistive element 1 and the voltage when the external operating magnetic field H was changed was measured. Note that the external operating magnetic field H is applied in a direction parallel to the direction of the magnetic moment of the precipitated magnetic particles 7 of the pinning layer 3.

As shown in FIG. 4A, the external operating magnetic field H
Is not applied, the magnetization of the free layer 5 is in a random direction, and the magnetization of the pinning layer 3 operates as a bias.

When the external operating magnetic field H is applied in the same direction as the direction of the magnetic moment of the deposited magnetic particles 7 of the pinning layer 3 as shown in a region D of FIGS.
As shown in (b), in the magnetoresistive element 1, the magnetization direction of the free layer 5 and the magnetization direction of the pinning layer 3 are the same, and the magnetization and the electric resistance are reduced.

When the external operating magnetic field H is applied in a direction opposite to the direction of the magnetic moment of the deposited magnetic particles 7 of the pinning layer 3 as shown in a region E of FIGS.
As shown in (c), in the magnetoresistance effect element 1, the magnetization direction of the free layer 5 and the magnetization direction of the pinning layer 3 become antiparallel, the magnetization increases positively, and the electric resistance increases.

As shown in a region F of FIGS. 2 and 3, the external operating magnetic field H is applied in a direction opposite to the direction of the magnetic moment of the deposited magnetic particles 7 of the pinning layer 3 and between the pinning layer 3 and the antiferromagnetic layer 2. When an external operating magnetic field H larger than the magnetic exchange coupling _Hex is applied, as shown in FIG. 4D, in the magnetoresistive element 1, the magnetization direction of the pinning layer 3 is reversed and the free layer 5 Becomes parallel to the magnetization direction of the pinning layer 3, the magnetization becomes maximum, and the electric resistance decreases.

In this embodiment, since the direction of the magnetic moment of the deposited magnetic particles 7 is fixed by the antiferromagnetic layer 2, the polarity of the pinning layer 3 is not easily inverted due to the fluctuation of the external magnetic field. Further, the external operating magnetic field H is hard to fluctuate in the magnetic exchange coupling _Hex because the direction of the magnetic moment of the precipitated magnetic particles 7 of the pinning layer 3 is stable. Therefore, the device is hardly affected by an external magnetic field and can operate stably. Further, the magnetic moment of the precipitated magnetic particles 7 in the free layer 5 changes in accordance with the external operating magnetic field H, so that the magnetic moment becomes parallel or anti-parallel to the magnetic moment in the pinning layer 3 to obtain a large magnetoresistance change. Can be.

Next, a method of manufacturing the magnetoresistive element shown in FIG. 1 will be described. 5A and 5B are cross-sectional views illustrating a method of manufacturing a magnetoresistive element in the order of steps.

First, as shown in FIG. 5A, the substrate 9 is, for example, # 7059 manufactured by Corning Co.
Using a glass substrate, the substrate 9 is mounted on a ternary DC magnetron sputtering apparatus. And, for example,
In an Ar gas atmosphere at a pressure of 0.4 Pa, a DC power supply is used, and as a film forming condition of the antiferromagnetic layer 2, for example,
A PtMn target with a power of 200 W is used. First
As the film forming conditions for the granular layer 6a, for example, an electric power of 50 W and an Ag or AgCu alloy target are used for the matrix phase, and an electric power of 250 W and an FeC
o Use the target. As a film forming condition of the nonmagnetic layer 4, for example, an electric power of 50 W, an Ag or AgCu alloy target is used. As a film forming condition of the second granular layer, for example, a power of 50 W, Ag or AgC
A uCo target is used, and a FeCo target is used for the deposited magnetic particles 7 with a power of 150 W. The antiferromagnetic layer 2, the first granular layer 6a, the nonmagnetic layer 4, and the second granular layer 6b are simultaneously formed on the substrate 6.
At this time, the antiferromagnetic layer 2 is formed in a later heat treatment step.
The first and second granular layers 6a and 6b are formed in a metastable state while exhibiting magnetic exchange coupling and being formed into a regular lattice.

Next, as shown in FIG. 5B, while applying a magnetic field to these samples, for example, the temperature was increased at a rate of 25 ° C./min in an Ar gas atmosphere to a temperature of 270 ° C. At 1
After heating and holding for an hour, the mixture is cooled to room temperature in a furnace. Thereby, the antiferromagnetic layer 2 has a regular lattice.

On the other hand, in the first granular layer 6a, the magnetic particles 8 are deposited and grown by this heating. At the same time, the pinning layer 3 is magnetically exchange-coupled with the laminated antiferromagnetic layer 2 and the direction of the magnetic moment of the precipitated magnetic particles 7 is fixed in the direction of the applied magnetic field.

The nonmagnetic layer 4 prevents magnetic coupling of the precipitated magnetic particles 7 of the first and second granular layers 6a and 6b during the heat treatment in a magnetic field. Further, the second granular layer 6b
In the free layer 5, the magnetic particles 8 are deposited and grown, and the free layer 5 in which the direction of the magnetic moment of the deposited magnetic particles 7 is not fixed is obtained.

Thus, by performing the heat treatment while applying a magnetic field, the antiferromagnetic layer 2 becomes a regular lattice,
The direction of the magnetic moment of the precipitated magnetic particles 7 of the first granular layer 6a is fixed to the direction of the applied magnetic field. Further, the non-magnetic layer 4 can prevent magnetic coupling with the first and second granular layers 6a and 6b.

In this embodiment, the magnetoresistive element 1
Each layer is formed by a sputter deposition method, but is not limited thereto. For example, a film can be formed by a high vacuum deposition method, an ion beam sputtering method, or the like.

Next, a second embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. 6, the same components as those in FIGS. 1 to 5 showing the first embodiment of the present invention are denoted by the same reference numerals, and detailed description thereof will be omitted. 6A and 6B are cross-sectional views illustrating a method of manufacturing a magnetoresistive element in the order of steps.

The present embodiment differs from the first embodiment only in the order in which the layers of the magnetoresistive element 1 are laminated, and the other structures and manufacturing methods are the same.

In this embodiment, as shown in FIG. 6A, a second granular layer 6b, a nonmagnetic layer 4,
The first granular layer 6a and the antiferromagnetic layer 2 are formed in the stacking order, and are heat-treated in a magnetic field to obtain the magnetoresistive element 1 as shown in FIG.

Thus, heat treatment is performed in a magnetic field,
Granular layer 6b, nonmagnetic layer 4, and first granular layer 6
Since the layers are stacked in the order of a, magnetic coupling with the first and second granular layers 6a and 6b can be prevented.
Furthermore, since the first granular layer 6a is formed below the antiferromagnetic layer 2, the magnetic moment of the precipitated magnetic particles 7 is fixed in the direction of the applied magnetic field.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 7 shows the first embodiment of the present invention.
The same components as those in FIGS. 1 to 5 showing the embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. 7A and 7B are cross-sectional views illustrating a method of manufacturing a magnetoresistive element in the order of steps.

The present embodiment differs from the first embodiment only in the order in which the respective layers of the magnetoresistive element 1 are laminated, and the other structures and manufacturing methods are the same.

In this embodiment, as shown in FIG. 7A, an antiferromagnetic layer 2 and a first granular layer 6
a, nonmagnetic layer 4, second granular layer 6b, nonmagnetic layer 4,
The first granular layer 6a and the antiferromagnetic layer 2 are formed in the lamination order, and are subjected to a heat treatment in a magnetic field to obtain the magnetoresistive element 1 as shown in FIG.

Thus, heat treatment is performed in a magnetic field,
Since the nonmagnetic layer 4, the first granular layer 6 a, and the antiferromagnetic layer 2 are laminated on both sides of the granular layer 6 b in the center, magnetic coupling with the first and second granular layers 6 a, 6 b is performed. Can be prevented. Further, since the first granular layer 6a is in contact with the antiferromagnetic layer 2, the magnetic moment of the precipitated magnetic particles 7 is fixed in the direction of the applied magnetic field.

In any of the above embodiments, the composition of each layer of the magnetoresistive element 1 is not limited to that of the embodiment, and the antiferromagnetic layer 2 performs magnetic exchange coupling at the heat treatment temperature of the granular layer 6. Any composition that can be expressed and form a regular lattice may be used. Further, the pinning layer 3 preferably has a larger volume ratio of the magnetic particles 8 than that of the free layer 4 in order to perform magnetic exchange coupling with the antiferromagnetic layer 2. Further, it is preferable that the nonmagnetic layer 4 has the same composition as the parent phase of the granular layer 6 and has a minimum thickness that prevents magnetic coupling between the pinning layer 3 and the free layer 4. Furthermore, the free layer 5
Is preferably a composition having high magnetic field sensitivity.

[0042]

FIG. 5 shows an embodiment of the present invention.
(B) A magnetoresistive element having the structure of the embodiment shown in FIGS. 6 (b) and 7 (b) and a magnetoresistive element of a comparative example different from the structure of the present invention were prepared, and the characteristics of both were compared. The results obtained will be described. Table 1 shows the film configurations and the MR ratios of the magnetoresistive elements of the example of the present invention and the comparative example.

In Example No. 1, as shown in FIG. 5B, an antiferromagnetic layer 2
A 0 nm PtMn layer is formed, a 4 nm thick Ag- (FeCo) _{50 %} by _volume film is formed thereon as a pinning layer 3, and a 1 nm thick Ag film is formed thereon as a nonmagnetic layer 4. Was formed thereon, and an Ag- (FeCo) _{30 %} by _volume film having a thickness of 5 nm was formed as the free layer 5 thereon. In addition, Ag- (F
eCo) _{50 % by volume} film refers to a film in which the parent phase is Ag and the parent phase contains 50% by volume of FeCo alloy as precipitated magnetic particles 7. Similarly, Ag- (FeCo) _{30
The volume %} film refers to a film in which the parent phase is Ag and the parent phase contains 30% by volume of FeCo alloy as the precipitated magnetic particles 7.

In the embodiment No. 2, as shown in FIG.
As shown in FIG.
A 0 nm PtMn layer is formed, and a free layer 5 is formed thereon.
Ag with a thickness of 4 nm₉₀Cu_Ten-(FeCo)_{50 volume %}film
Is formed thereon, and a nonmagnetic layer 4 having a thickness of 1 nm is formed thereon.
An Ag film is formed, and a film thickness as a pinning layer 3 is formed thereon.
Is 5nm Ag₉₀Cu_Ten-(FeCo)_{30 volume %}To form a film
Was. In addition, Ag₉₀Cu _Ten-(FeCo)_{50 volume %}The membrane is the mother
Phase is Ag₉₀Cu_TenAnd the precipitated magnetic particles 7
As a film containing 50% by volume of an FeCo alloy.
Show. Similarly, Ag₉₀Cu_Ten-(FeCo)_{30 volume %}With membrane
Means that the mother phase is Ag₉₀Cu_TenAnd the precipitated magnetism in this matrix
The particles 7 contain 30% by volume of an FeCo alloy.
FIG.

In Example No. 3, as shown in FIG. 6B, a free layer 5
m-Ag- (FeCo) _{30 vol %} film is formed thereon, a 1 nm-thick Ag film is formed thereon as the nonmagnetic layer 4, and a 4 nm-thick Ag film is formed thereon as the pinning layer 3. -(FeC
o) A _{50 %} by _volume film is formed, and an antiferromagnetic layer 2 is formed thereon.
A PtMn layer having a thickness of 20 nm was formed.

In Example No. 4, as shown in FIG. 7B, an antiferromagnetic layer 2 having a thickness of 2
A 0 nm PtMn layer is formed, a 4 nm thick Ag- (FeCo) _{50 %} by _volume film is formed thereon as a pinning layer 3, and a 1 nm thick Ag film is formed thereon as a nonmagnetic layer 4. Was formed thereon, and an Ag- (FeCo) _{30 %} by _volume film having a thickness of 5 nm was formed as the free layer 5 thereon. Further, an Ag film having a thickness of 1 nm is formed thereon as the nonmagnetic layer 4, and an Ag- (Fe) film having a thickness of 4 nm is formed thereon as the pinning layer 3.
(Co) A _{50 %} by _volume film was formed, and PtMn having a thickness of 20 nm was formed thereon as the antiferromagnetic layer 2.

[0047] In Comparative Example No.1, the film thickness was formed 30nm of Ag- (FeCo) _{30 body volume%} film on the substrate 9.

In Comparative Example No. 2, an Ag ₉₀ Cu _10- (FeCo) _{50 %} by _volume film having a thickness of 30 nm was formed on the substrate 9.

[0049]

[Table 1]

In Examples Nos. 1 to 4 and Comparative Examples Nos. 1 and 2, the magnetic field strength was -200 Oe to 200 Oe.
The MR ratio in a magnetic field was measured. Table 1 shows the results.

As shown in Table 1 above, Example No. 1 within the scope of the present invention had an MR ratio of 11.4%. Also,
Example No. 2 had an MR ratio of 10.2%. Example No.
Sample No. 3 had an MR ratio of 10.1%. Example No. 4 is MR
The ratio was 15.3%. That is, in Examples Nos. 1 to 4, the MR ratio exceeded 10%.

On the other hand, Comparative Example No. 1 had an MR ratio of 5.1%. Comparative Example No. 2 had an MR ratio of 4.8%. In all the comparative examples, the MR ratio was less than 10%.

[0053]

As described above in detail, in the present invention, one of the granular layers bonded via the nonmagnetic layer fixes the direction of the magnetic moment of the deposited magnetic particles in one direction,
The other granular layer has a configuration in which the direction of the magnetic moment of the precipitated magnetic particles is changed according to the external magnetic field, so that the magnetic moments are parallel or anti-parallel, and a large change in magnetoresistance can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a magnetoresistive element according to a first embodiment of the present invention.

FIG. 2 is a graph showing a magnetization curve.

FIG. 3 is a graph showing a change in magnetoresistance with respect to an external magnetic field.

FIGS. 4A to 4D are cross-sectional views showing the behavior of the magnetoresistive element of the present invention due to an external magnetic field.

FIGS. 5A and 5B are cross-sectional views illustrating a method of manufacturing the magnetoresistive element according to the first embodiment of the present invention in the order of steps.

FIGS. 6A and 6B are cross-sectional views illustrating a method of manufacturing a magnetoresistive element according to a second embodiment of the present invention in the order of steps.

FIGS. 7A and 7B are cross-sectional views illustrating a method of manufacturing a magnetoresistive element according to a third embodiment of the present invention in the order of steps.

[Explanation of symbols]

Reference Signs List 1: magnetoresistive element, 2: antiferromagnetic layer, 3: pinning layer, 4: nonmagnetic layer, 5: free layer, 6: granular layer, 6a: first granular layer, 6b: second granular layer, 7 8; magnetic particles,
9; substrate, D, E, F; area, H: external operating magnetic field,
H _ex ; magnetic exchange coupling

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Makoto Shiraki 10-1 Nakazawa-cho, Hamamatsu-shi, Shizuoka F-term in Yamaha Corporation (reference) 5D034 BA05 BA21 CA08 DA07

Claims (3)

[Claims] 1. A magnetoresistive element having an antiferromagnetic layer, a plurality of granular layers containing magnetic particles, and a nonmagnetic layer, wherein one of the plurality of granular layers has a deposited magnetic layer. The direction of the magnetic moment of the particles is a pinning layer fixed in one direction by the antiferromagnetic layer, and the other granular layer is a free layer in which the direction of the magnetic moment of the precipitated magnetic particles changes according to an external magnetic field. A magnetoresistive element comprising: 2. The magnetoresistive element according to claim 1, wherein a nonmagnetic layer is interposed between the pinning layer and the free layer. 3. A step of laminating an antiferromagnetic layer, a first granular layer containing magnetic particles, a nonmagnetic layer, and a second granular layer containing magnetic particles in this order, wherein the antiferromagnetic layer and the first granular layer are stacked. Heat treating the non-magnetic layer and the second granular layer in a magnetic field to precipitate magnetic particles contained in the first and second granular layers, and to form the antiferromagnetic layer into a regular lattice,
Producing a magnetoresistive effect element comprising: a step of magnetically exchanging a first granular layer with the antiferromagnetic layer and fixing a magnetic moment of magnetic particles of the first granular layer in the direction of the magnetic field. Method.