JP2000216456A - Magneto-resistance effect element and thin film magnetic head using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase an anti-corrosion property and generate a large exchange anisotropic magnetic field by setting a composition ratio of a specified alloy from which an antiferromagnetic layer disposed under a fixed magnetic layer is formed within a specified range. SOLUTION: An antiferromagnetic layer 4 formed below a free magnetic layer 1 is formed under a fixed magnetic layer 3. A composition ratio of an element X" of an X"-Mn alloy used for the antiferromagnetic layer 4 is between 44 and 57 at%. When the antiferromagnetic layer 4 is formed under the fixed magnetic layer 3, if a composition ratio of the element X" of the X"-Mn alloy used for the antiferromagnetic layer 4 is between 44 and 57 at%, an exchange anisotropic magnetic field of 400(Oe) or above can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive element using an exchange-coupling film capable of improving corrosion resistance and obtaining a larger exchange anisotropic magnetic field, and using the magnetoresistive element. The present invention relates to a thin-film magnetic head.

[0002]

2. Description of the Related Art A spin valve type thin film element is a kind of a giant magnetoresistive (GMR) element utilizing a giant magnetoresistive effect, and detects a recording magnetic field from a recording medium such as a hard disk.

The spin-valve thin-film element has several advantages, such as a relatively simple structure among GMR elements and a change in resistance with a weak magnetic field.

The spin-valve thin-film element has the simplest structure and comprises an antiferromagnetic layer, a pinned magnetic layer, a non-magnetic conductive layer and a free magnetic layer.

The antiferromagnetic layer and the pinned magnetic layer are formed in contact with each other, and the magnetization direction of the pinned magnetic layer is changed by an exchange anisotropic magnetic field generated at the interface between the antiferromagnetic layer and the pinned magnetic layer. A single magnetic domain is formed in a certain direction and fixed.

[0006] The magnetization of the free magnetic layer is aligned in a direction crossing the magnetization direction of the fixed magnetic layer by the bias layers formed on both sides thereof.

The antiferromagnetic layer is made of an Fe-Mn (iron-manganese) alloy film or a Ni-Mn (nickel-manganese) alloy film, and the pinned magnetic layer and the free magnetic layer are made of Ni-F.
e (nickel-iron) alloy film, non-magnetic conductive layer Cu
(Copper) film and Co-Pt (cobalt-
A (platinum) alloy film or the like is generally used.

In this spin-valve thin film element, when the magnetization direction of the free magnetic layer changes due to a leakage magnetic field from a recording medium such as a hard disk, the electric resistance changes in relation to the fixed magnetization direction of the fixed magnetic layer. The leakage magnetic field from the recording medium is detected by the voltage change based on the change in the electric resistance value.

As described above, an Fe—Mn alloy film or a Ni—Mn alloy film is used for the antiferromagnetic layer. However, the Fe—Mn alloy film has low corrosion resistance and has an exchange anisotropic magnetic field. And the blocking temperature is as low as about 150 ° C. With a low blocking temperature,
A problem arises that the exchange anisotropic magnetic field disappears due to an increase in the element temperature during the head manufacturing process or during the operation of the head.

On the other hand, the Ni—Mn alloy film is made of Fe—
Compared with the Mn alloy film, the exchange anisotropic magnetic field is relatively large,
Moreover, the blocking temperature is as high as about 300 ° C. Therefore, it is more preferable to use a Ni—Mn alloy film than an Fe—Mn alloy film for the antiferromagnetic layer.

[0011]

SUMMARY OF THE INVENTION As described above, Ni
The Mn alloy has a relatively large exchange anisotropic magnetic field and a high blocking temperature of about 300 ° C.
Although it has excellent characteristics as compared with the eMn alloy, it cannot be said that the corrosion resistance is sufficient as in the case of the FeMn alloy.

The present invention has been made to solve the above-mentioned conventional problems. In particular, the present invention uses an exchange coupling film capable of improving corrosion resistance and generating a larger exchange anisotropic magnetic field. And a thin-film magnetic head using the magnetoresistive element.

[0013]

According to the present invention, there is provided a magnetoresistive element comprising a nonmagnetic conductive layer laminated above and below a free magnetic layer, and a nonmagnetic conductive layer on one of the nonmagnetic conductive layers and the other nonmagnetic conductive layer. The pinned magnetic layer located below and in contact with one of the pinned magnetic layers above and below the other pinned magnetic layer, the magnetization directions of the pinned magnetic layers are fixed in a fixed direction by an exchange anisotropic magnetic field. An antiferromagnetic layer; and a bias layer for aligning the magnetization direction of the free magnetic layer with a direction crossing the magnetization direction of the pinned magnetic layer.
(Where X ″ is Pt, Pd, Ir, Rh, Ru, Os
And the composition ratio of X ″ of the X ″ —Mn alloy forming the antiferromagnetic layer located on one of the pinned magnetic layers is at %
The composition ratio of X ″ of the X ″ -Mn alloy forming the antiferromagnetic layer located below the other pinned magnetic layer is at%, and is in the range of 44 to 57. It is characterized by being within.

In the present invention, the composition ratio of X ″ of the X ″ -Mn alloy forming the antiferromagnetic layer located on the one fixed magnetic layer is at% and is in the range of 50 to 56. ,
The X ″ -Mn alloy forming the antiferromagnetic layer located below the other pinned magnetic layer has a composition ratio of X ″ of at.
It is preferably within the range of 55.

As described above, in the present invention, the platinum group element (P
t, Pd, Ir, Rh, Ru, Os), two or more elements are selected and an antiferromagnetic layer comprising the platinum group element and Mn is used. Corrosion resistance can be improved and a larger exchange anisotropic magnetic field can be generated as compared with a used Ni-Mn alloy or the like. Therefore, it is possible to firmly fix the magnetization of the fixed magnetic layer in a fixed direction, and it is possible to obtain excellent reproduction characteristics as compared with the related art.

As described above, depending on whether the antiferromagnetic layer formed of the X ″ -Mn alloy is formed on or below the ferromagnetic layer, the composition ratio of the platinum group element in the whole is changed. Thus, a larger exchange anisotropic magnetic field can be obtained.

X ″ -M used as the antiferromagnetic layer
The element X ″ of the n-alloy is preferably Pt.

Further, the magnetoresistive element of the present invention is provided with a non-magnetic conductive layer laminated above and below a free magnetic layer, and on one of the non-magnetic conductive layers and below the other non-magnetic conductive layer. A pinned magnetic layer, and an antiferromagnetic layer which is in contact with one of the pinned magnetic layers and under the other pinned magnetic layer to fix the magnetization direction of each pinned magnetic layer in a fixed direction by an exchange anisotropic magnetic field. And a bias layer for aligning the magnetization direction of the free magnetic layer in a direction crossing the magnetization direction of the pinned magnetic layer, and comprising an X-Mn-X 'alloy (where X is Pt, P
d, Ir, Rh, Ru, or Os, which is one or more elements, and the element X ′ is Ne, Ar,
Kr, Xe, Be, B, C, N, Mg, Al, Si,
P, Ti, V, Cr, Fe, Co, Ni, Cu, Zn,
Ga, Ge, Zr, Nb, Mo, Ag, Cd, Ir, S
n, Hf, Ta, W, Re, Au, Pb, and at least one of the rare earth elements). The composition ratio of X + X 'of the X-Mn-X' alloy forming the magnetic layer is at% and is in the range of 47 to 57, and forms the antiferromagnetic layer located below the other fixed magnetic layer. X-M
The composition ratio of X + X 'in the n-X' alloy is at%,
7 is within the range.

In the present invention, the composition ratio of X + X ′ of the X—Mn—X ′ alloy forming the antiferromagnetic layer located on the one fixed magnetic layer is at%, and is in the range of 50 to 56. The composition ratio of X + X ′ of the X—Mn—X ′ alloy forming the antiferromagnetic layer located below the other pinned magnetic layer is a
The t% is preferably in the range of 46 to 55.

As described above, in the present invention, the antiferromagnetic material composed of at least one element X and Mn selected from the platinum group elements is added to the gap between the crystal lattice composed of the elements X and Mn. A larger exchange anisotropic magnetic field can be obtained by invading the element X 'or substituting a part of the lattice points of the crystal lattice composed of the elements X and Mn with the element X'. It is considered that the reason why a larger exchange anisotropic magnetic field is obtained by containing the element X 'is that the lattice constant of the antiferromagnetic layer can be increased as compared with the case where the element X' is not added. The X-Mn-X 'alloy is also excellent in corrosion resistance.

Further, as described above, the composition ratio of X + X 'in the whole depends on whether the antiferromagnetic layer formed of the X-Mn-X' alloy is formed above or below the ferromagnetic layer. , It is possible to obtain a larger exchange anisotropic magnetic field.

In the present invention, the element X 'is Ne, A
Preferably, it is one or more of r, Kr, and Xe.

In the present invention, the element X of the X-Mn-X 'alloy used as the antiferromagnetic layer is preferably Pt.

In the present invention, the composition ratio of the element X 'is at%, preferably in the range of 0.2 to 10, more preferably the composition ratio of the element X' is at%.
It is in the range of 0.5 to 5.

It has been confirmed by experiments described later that the formation of the antiferromagnetic layer under the above conditions can dramatically increase the exchange anisotropic magnetic field generated at the interface between the antiferromagnetic layer and the ferromagnetic layer. I have.

In the present invention, the X-Mn-X 'alloy used as the antiferromagnetic layer is preferably formed by a sputtering method. The X-Mn-X 'alloy formed by the sputtering method is in a state in which the element X' in the film is in the form of a substitution or interstitial solid solution.

Further, the thin-film magnetic head according to the present invention is characterized in that a shield layer is formed above and below the above-mentioned magnetoresistive effect element via a gap layer.

[0028]

FIG. 1 is a cross-sectional view of the structure of a dual spin-valve thin film element according to an embodiment of the present invention as viewed from the ABS side. In FIG. 1, only the central portion of the element extending in the X direction is shown broken.

This dual spin-valve thin film element is
It is provided at a trailing side end of a floating slider provided in a hard disk device, and detects a recording magnetic field of a hard disk or the like. The moving direction of the magnetic recording medium such as a hard disk is the Z direction, and the direction of the leakage magnetic field from the magnetic recording medium is the Y direction.

As shown in the figure, an underlayer 6 made of Ta or the like, an antiferromagnetic layer 4, a pinned magnetic layer 3, a nonmagnetic conductive layer 2, and a free magnetic layer 1 are successively laminated from below. . Further, on the free magnetic layer 1, a nonmagnetic conductive layer 2, a fixed magnetic layer 3, an antiferromagnetic layer 4, and a protective layer 7 are successively laminated.

Hard bias layers 5 and 5 and conductive layers 8 and 8 are laminated on both sides of the multilayer film from the base layer 6 to the protective layer 7.

In the present invention, the free magnetic layer 1 and the pinned magnetic layer 3 are made of a NiFe alloy, a CoFe alloy, a Co alloy,
It is formed of Co, CoNiFe alloy or the like.

Although the free magnetic layer 1 is formed as a single layer as shown in FIG. 1, it may be formed in a multilayer structure. That is, the free magnetic layer 1 is made of, for example, NiFe.
It may have a structure in which an alloy and a CoFe alloy are laminated, or may have a structure in which a NiFe alloy and Co are laminated.

The nonmagnetic conductive layer 2 interposed between the free magnetic layer 1 and the pinned magnetic layer 3 is formed of Cu.
Further, the hard bias layers 5 and 5 are made of, for example, Co-Pt.
(Cobalt-Platinum) alloy, Co-Cr-Pt (Cobalt-Chromium-Platinum) alloy, etc., and the conductive layers 8, 8 are made of Cu (copper), W (tungsten), Cr (chromium), or the like. Is formed.

In the present invention, the antiferromagnetic layer 4 formed above or below the fixed magnetic layer 3 is made of an X ″ -Mn alloy (where X ″ is Pt, Pd, Ir, Rh, Ru, Ru, Os). (Which is any two or more of these elements). The X ″ -Mn alloy used as the antiferromagnetic layer 4 in the present invention is superior in corrosion resistance to FeMn alloy, NiMn alloy and the like conventionally used as the antiferromagnetic layer, and has a high blocking temperature. Further, it has excellent properties as an antiferromagnetic material such as a large exchange anisotropic magnetic field (Hex).

As shown in FIG. 1, the antiferromagnetic layer 4 formed below the free magnetic layer 1 is formed below the fixed magnetic layer 3 and is used as the antiferromagnetic layer 4. The composition ratio of the element X ″ of the X ″ -Mn alloy to be
５７57, preferably the composition ratio of the element X ″ in the X ″ —Mn alloy is at% and is in the range 46-55.

When the antiferromagnetic layer 4 is formed below the fixed magnetic layer 3, the composition ratio of the element X ″ of the X ″ —Mn alloy used as the antiferromagnetic layer 4 is in the range of 44 to 57 at%. Within this range, an exchange anisotropic magnetic field of 400 (Oe) or more can be obtained. When the composition ratio of the element X ″ in the X ″ —Mn alloy is in the range of 46 to 55 at%, 600%
It is possible to obtain an exchange anisotropic magnetic field of (Oe) or more.

The antiferromagnetic layer 4 formed above the free magnetic layer 1 is formed on the pinned magnetic layer 3, and the X ″ -Mn used as the antiferromagnetic layer 4 is used.
The composition ratio of the element X ″ in the alloy is at% in the range of 47 to 57, preferably the composition ratio of the element X ″ in the X ″ -Mn alloy is at% in the range of 50 to 56.

When the antiferromagnetic layer 4 is formed on the pinned magnetic layer 3, the composition ratio of the X ″ —Mn alloy element X ″ is at% and is in the range of 47 to 57. , 400 (O
e: Oersted) or more exchange anisotropic magnetic field. When the composition ratio of the element X ″ in the X ″ —Mn alloy is at% and is in the range of 50 to 56, 600 (O
e) It is possible to obtain the above exchange anisotropic magnetic field.

Within this composition range, the difference between the lattice constant of the pinned magnetic layer 3 before the heat treatment and the lattice constant of the antiferromagnetic layer 4 can be increased. Therefore, by performing the heat treatment, the crystal structure of a part of the antiferromagnetic layer 4 at the interface is transformed from the disordered lattice to the ordered lattice required for exhibiting the exchange anisotropic magnetic field. It is possible.

If the interface structure is in a matched state, the crystal structure of the antiferromagnetic layer 4 is unlikely to be transformed from an irregular lattice to a regular lattice even if heat treatment is performed, and therefore, an exchange anisotropic magnetic field cannot be obtained. The problem arises.

When the antiferromagnetic layer 4 is formed of a PtMn alloy, the ratio c / a of the lattice constants a and c of the antiferromagnetic layer 4 after the heat treatment is in the range of 0.93 to 0.99. Is preferably within the range.

In the present invention, the interface structure between the pinned magnetic layer 3 and the antiferromagnetic layer 4 shown in FIG.
The crystalline structure of at least part of the at the interface antiferromagnetic layer 4 has a L1 ₀ type of face-centered tetragonal lattice (hereinafter referred to as ordered lattice).

[0044] Here, the L1 ₀ type face-centered tetragonal lattice, of the six sides of the unit cell, the center of the four sides of the side X "atoms (X" = Pt, Pd, Ir, Rh, Ru, Os , And Mn atoms occupy the corners of the unit cell and the centers of the upper and lower surfaces.

In the present invention, the fact that the crystal orientations of the pinned magnetic layer 3 and the antiferromagnetic layer 4 differ from each other
The structure of the interface between the antiferromagnetic layer 4 and the antiferromagnetic layer 4 is preferable because it is likely to be in a mismatched state.

In the present invention, an X-Mn alloy (where X
Is one or more of Pt, Pd, Ir, Rh, Ru, and Os), and the element X ′ is added as a third element to form the lattice of the antiferromagnetic layer 4. The constant can be increased, and the interface structure between the antiferromagnetic layer 4 and the pinned magnetic layer 3 before the heat treatment can be brought into a non-matching state.

X-Mn obtained by adding an element X 'to an X-Mn alloy
—X ′ alloy is an interstitial solid solution in which element X ′ has penetrated into the space of a spatial lattice composed of elements X and Mn, or one of the lattice points of the crystal lattice composed of elements X and Mn. Part is a substitution type solid solution substituted by the element X ′. Here, a solid solution refers to a solid in which components are uniformly mixed over a wide composition range. In the present invention, the element X is preferably Pt.

In the present invention, the X-Mn-X 'alloy is formed by sputtering. By sputtering, the X-Mn-X 'alloy is formed in a non-equilibrium state,
The deposited X-Mn-X 'alloy has an element X' in the film,
Penetrate into the space of the spatial lattice composed of the elements X and Mn,
Alternatively, part of the lattice points of the crystal lattice composed of the elements X and Mn is replaced with the element X ′. As described above, when the element X ′ forms a solid solution in the lattice of the X—Mn alloy in an interstitial or substitutional manner, the lattice is expanded, and the lattice constant of the antiferromagnetic layer 4 is reduced by the element X ′. It becomes larger than the case without addition.

In the present invention, various elements can be used as the element X '. However, when highly reactive halogen or O (oxygen) is used, these elements are selectively bonded only to Mn. It is considered that the crystal structure of face-centered cubic cannot be maintained, which is not preferable. Specific elements X 'in the present invention are Ne, Ar, Kr, Xe, Be,
B, C, N, Mg, Al, Si, P, Ti, V, Cr,
Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, N
b, Mo, Ag, Cd, Ir, Sn, Hf, Ta, W,
Re, Au, Pb, and rare earth elements (Sc, Y and lanthanoids (La, Ce, Pr, Nd, Pm, Sm, Eu,
Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu))
Is one or more elements.

The lattice constant of the antiferromagnetic layer 4 can be increased by sputtering using any of the various elements X 'described above. In particular, when the substitution-type solid solution element X' is used. If the composition ratio of the element X ′ is too large, the antiferromagnetic property is reduced, and the exchange coupling magnetic field generated at the interface with the fixed magnetic layer 3 is reduced.

In particular, in the present invention, it is preferable to use a rare gas element (one or more of Ne, Ar, Kr, and Xe) of an inert gas which forms a solid solution in an interstitial form as the element X '. I have. Since the rare gas element is an inert gas, even if the rare gas element is contained in the film, it does not greatly affect the antiferromagnetic characteristics. Further, Ar or the like is conventionally used as a sputtering gas in a sputtering apparatus. It is a gas to be introduced, and Ar can easily penetrate into the film simply by appropriately adjusting the gas pressure and the energy of the sputtered particles.

When a gas-based element is used as the element X ', it is difficult to contain a large amount of the element X' in the film. Just by exchanging the exchange coupling magnetic field generated by the heat treatment,
Experiments have shown that the size can be dramatically increased.

The X-rays used as the antiferromagnetic layer 4
When the element X 'of the Mn-X' alloy is, for example, a gas-based element, the element X 'escapes from the film by performing a heat treatment, and the composition of the element X' at the stage when the film is formed. The composition ratio of the element X ′ after the heat treatment becomes smaller than the ratio, or the X ′ completely escapes from the film,
In some cases, the composition becomes X-Mn. However, if the interface structure between the pinned magnetic layer 3 and the antiferromagnetic layer 4 in the film formation stage (before heat treatment) is in a non-matching state, heat treatment should be performed. Thereby, the crystal structure of the antiferromagnetic layer 4 is appropriately transformed from an irregular lattice (face-centered cubic lattice) to a regular lattice, and a large exchange anisotropic magnetic field can be obtained.

In the case of the antiferromagnetic layer 4 formed below the free magnetic layer 1, the composition ratio of X + X 'of the X-Mn-X' alloy used as the antiferromagnetic layer 4 is a
t% in the range of 44 to 57, preferably X-Mn
The composition ratio of X + X 'in the -X' alloy is at%,
Within the range.

In the case of the antiferromagnetic layer 4 formed above the free magnetic layer 1, the composition ratio of X + X ′ of the X—Mn—X ′ alloy used as the antiferromagnetic layer 4 is a
at%, in the range of 47-57, preferably X-M
The composition ratio of X + X 'in the n-X' alloy is at%, and is 50 to 5%.
6 is within the range.

Within the above composition range, the difference between the lattice constant of the fixed magnetic layer 3 before the heat treatment and the lattice constant of the antiferromagnetic layer 4 can be increased, and the interface structure before the heat treatment is brought into a non-matching state. Therefore, by performing heat treatment, the crystal structure of a part of the antiferromagnetic layer 4 at the interface is transformed from the disordered lattice to the ordered lattice required for exhibiting the exchange anisotropic magnetic field. Is possible.

When the antiferromagnetic layer 4 is formed of an X-Mn-X 'alloy, the composition ratio of the element X' is at% and
It is in the range of 0.2 to 10, and a more preferred composition range is at%, and in the range of 0.5 to 5.

If the composition ratio of the element X 'is adjusted within the above range, the lattice constant of the antiferromagnetic layer 4 at the film formation stage (before the heat treatment) can be increased. The exchange coupling magnetic field generated at the interface between the magnetic layer and the pinned magnetic layer 3 can be increased as compared with the case where the element X 'is not contained.

The ratio X: M of the composition ratio between the element X and Mn
n is preferably in the range of 4: 6 to 6: 4.

In this dual spin-valve thin film element, the fixed magnetic layer 3 is formed by an exchange anisotropic magnetic field as shown in FIG.
The magnetization of the free magnetic layer 1 is affected by the hard bias layers 5 and 5 and is fixed in a single magnetic domain.
It is aligned in the direction.

When a steady current is applied from the conductive layer 8 to the free magnetic layer 1, the nonmagnetic conductive layer 2, and the fixed magnetic layer 3 and a magnetic field is applied from the recording medium in the Y direction, the magnetization of the free magnetic layer 1 is Fluctuates from the X direction to the Y direction. At this time, spin-dependent scattering of conduction electrons occurs at the interface between the nonmagnetic conductive layer 2 and the free magnetic layer 1 and at the interface between the nonmagnetic conductive layer 2 and the fixed magnetic layer 3. As a result, the electric resistance changes, and the leakage magnetic field from the recording medium is detected.

In the dual spin-valve type thin film element shown in FIG. 1, scattering of conduction electrons occurs at two interfaces between the nonmagnetic conductive layer 2 and the free magnetic layer 1, the nonmagnetic conductive layer 2 and the fixed magnetic layer. Since there are a total of four locations of two interfaces with the layer 3, it is possible to obtain a larger resistance change rate than a single spin-valve thin film element.

As described in detail above, according to the present invention, the antiferromagnetic layer 4 is made of an X ″ -Mn alloy (where X ″ is Pt, Pd,
Ir, Rh, Ru, or Os), preferably a PtMn alloy, by appropriately adjusting the composition ratio of the antiferromagnetic layer 4.
The interface structure between the antiferromagnetic layer 4 and the pinned magnetic layer 3 formed in contact with the antiferromagnetic layer 4 can be brought into a non-matching state, so that a larger exchange anisotropic magnetic field can be obtained. It is possible to improve the reproduction characteristics as compared with the related art. Alternatively, the antiferromagnetic layer 4 is made of an element X (where X is Pt, Pt).
d, Ir, Rh, Ru, and Os) and Mn, and a third element X ′
(Where X 'is Ne, Ar, Kr, Xe, Be, B,
C, N, Mg, Al, Si, P, Ti, V, Cr, F
e, Co, Ni, Cu, Zn, Ga, Ge, Zr, N
b, Mo, Ag, Cd, Ir, Sn, Hf, Ta, W,
One or two of Re, Au, Pb, and rare earth elements
), The lattice constant of the antiferromagnetic layer 4 can be increased as compared with the case where the element X 'is not added.
The interface structure between the antiferromagnetic layer 4 and the pinned magnetic layer 3 formed in contact with the antiferromagnetic layer 4 can be brought into a non-matching state, so that a larger exchange anisotropic magnetic field can be obtained. It is possible to increase.

It is preferable that the antiferromagnetic layer 4 and the pinned magnetic layer 3 have different crystal orientations, since the interface structure can be more easily brought into a non-matching state.

The reason that the exchange anisotropic magnetic field can be obtained by keeping the interface structure in a mismatched state is that the crystal structure of the antiferromagnetic layer 4 is changed from an irregular lattice to a regular lattice by performing heat treatment. This is because transformation can be performed, but if all the crystal structures are transformed into a regular lattice, a problem occurs in adhesion and the like. Therefore, it is preferable that only a part of the crystal structure is transformed into a regular lattice. For example, when the antiferromagnetic layer 4 is formed of a PtMn alloy, the ratio c / a of the lattice constants a and c of the antiferromagnetic layer 4 after the heat treatment is set to 0.1.
It is preferably in the range of 93 to 0.99 (by the way, when all the crystal structures are transformed into a regular lattice, the ratio c / a of the lattice constants a and c is 0.918).

FIG. 2 is a cross-sectional view of the structure of the read head on which the magnetoresistive element layer shown in FIG. 1 is formed, as viewed from the side facing the recording medium.

Reference numeral 20 denotes a lower shield layer made of, for example, a NiFe alloy.
0, a lower gap layer 21 is formed. 1 is formed on the lower gap layer 21, and an upper gap layer 23 is formed on the magnetoresistive element layer 22. On the layer 23, an upper shield layer 24 made of a NiFe alloy or the like is formed.

The lower gap layer 21 and the upper gap
The layer 23 is made of, for example, SiO_TwoAnd Al_TwoO _Three(Alumina) etc.
Formed of an insulating material. As shown in FIG.
The lower gap layer 21 to the upper gap layer 23
The length is the gap length Gl, and this gap length Gl is small.
It has become possible to cope with higher recording density.

[0069]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the antiferromagnetic layer is made of Pt--Mn--X '.
(X '= Ar) alloy, the amount of element X' and Pt-M
The relationship with the lattice constant of the nX 'alloy was examined. The film configuration used for the experiment was as follows: Si substrate / Alumina / Ta
(50) / Co ₉₀ Fe ₁₀ (30) / Pt—Mn—X ′
(300) / Ta (100). The numerical value in parentheses indicates the film thickness, and the unit is angstrom.

The antiferromagnetic layer is formed in a sputtering apparatus.
Three types of targets in which the ratio of Pt to Mn is 6: 4, 1: 1, and 4: 6 are prepared, and using each of the targets, while changing the introduction gas pressure of Ar as the element X ′, A Pt—Mn—X ′ (X ′ = Ar) alloy film was formed by DC magnetron sputtering and ion beam sputtering. The amount of X ′ (X ′ = Ar) occupying in the Pt—Mn—X ′ (X ′ = Ar) alloy film and the amount of Pt—Mn—
The relationship between X ′ (X ′ = Ar) and the lattice constant was measured. FIG. 3 shows the experimental results.

As shown in FIG. 3, even when the composition ratio of Pt and Mn is any of 6: 4, 1: 1, and 4: 6, the element X ′ (X ′ = Ar) It can be seen that the lattice constant of Pt—Mn—X ′ (X ′ = Ar) increases as the amount increases. The lattice constant of the NiFe alloy, CoFe alloy, or Co used as the pinned magnetic layer is in the range of about 3.5 to 3.6, as shown in FIG. In this experiment, the amount of the element X '(X' = Ar) was set to about 4 at%, and no experiment was conducted for a case where the content was larger than that. However, Ar which is the element X 'is a gas element. For this reason, even if the gas pressure is increased, it is difficult to contain Ar in the film.

Next, the Pt—Mn—
The X ′ (X ′ = Ar) alloy film was subjected to the following heat treatment step. As conditions in the heat treatment step, first, the temperature was raised for 3 hours, then the temperature of 240 ° C. was maintained for 3 hours, and further, the temperature was lowered for 3 hours. Note that the heat treatment vacuum degree was set to 5 × 10 ⁻⁶ Torr or less.

FIG. 4 shows that Pt—Mn—X ′ (X ′ = Ar)
4 is a graph showing the relationship between the amount of element X ′ (X ′ = Ar) in an alloy film and the magnitude of an exchange coupling magnetic field generated at the interface between the antiferromagnetic layer and the pinned magnetic layer by the heat treatment.

As shown in FIG. 4, the element X '(X' = A
It can be seen that as the amount of r) increases, the exchange coupling magnetic field increases. That is, when the element X ′ (X ′ = Ar) is added to PtMn, a larger exchange coupling magnetic field can be obtained as compared with the case where the element X ′ (X ′ = Ar) is not added.

Next, in the present invention, using another element X ′,
The antiferromagnetic layer is formed of a Pt—Mn—X ′ (X ′ = Mo) alloy, and the amount of element X ′ (X ′ = Mo) and Pt—Mn—X ′
The relation with the lattice constant of the (X ′ = Mo) alloy film was examined. The film configuration used in the experiment was as follows: Si substrate / alumina / Ta (50) / Co ₉₀ Fe ₁₀ (30) / Pt—Mn
-X '(300) / Ta (100). The numerical value in parentheses indicates the film thickness, and the unit is angstrom.

For the formation of the antiferromagnetic layer, a composite target in which a chip of the element X '(X' = Mo) is bonded to a target of PtMn is prepared, and the area ratio of the chip to the target is changed. , The element X 'in the film
(X ′ = Mo), the amount of the element X ′ (X ′ = Mo) was changed.
The relationship between the amount of Mo) and the lattice constant of the Pt—Mn—X ′ (X ′ = Mo) alloy was measured. FIG. 5 shows the experimental results.

As shown in FIG. 5, even when the composition ratio of Pt and Mn is 6: 4, 1: 1, or 4: 6, the element X '(X' = It can be seen that as the concentration of Mo) increases, the lattice constant of Pt—Mn—X ′ (X ′ = Mo) increases. In addition, NiFe alloy, CoFe alloy, or CoFe used as the pinned magnetic layer
Has a range of about 3.5 to 3.6 as shown in FIG.

Next, the Pt—Mn—
The X ′ (X ′ = Mo) alloy film was subjected to the following heat treatment step. As conditions in the heat treatment step, first, the temperature was raised for 3 hours, then the temperature of 240 ° C. was maintained for 3 hours, and further, the temperature was lowered for 3 hours. Note that the heat treatment vacuum degree was set to 5 × 10 ⁻⁶ Torr or less.

FIG. 6 shows that Pt—Mn—X ′ (X ′ = Mo)
4 is a graph showing a relationship between the concentration of an element X ′ (X ′ = Mo) in an alloy film and the magnitude of an exchange coupling magnetic field generated at an interface between an antiferromagnetic layer and a pinned magnetic layer by the heat treatment.

As shown in FIG. 6, regardless of the composition ratio of Pt to Mn of 6: 4, 1: 1, or 4: 6, the element X '(X' = Mo) amount is about 3at%
From the above, it is understood that the exchange coupling magnetic field gradually decreases. In particular, when the amount of element X '(X' = Mo) in the film is about 10 at% or more, the exchange coupling magnetic field is extremely small even if the composition ratio of Pt and Mn is 1: 1. This is not preferred.

Incidentally, the content of the element X ′ (X ′ = Mo) is appropriate, but at least the element X ′ (X ′ = Mo)
Mo) is not contained, that is, the element X '(X' =
Mo) It is preferable that the exchange coupling magnetic field be larger than when the amount is 0 at%.

When the composition ratio of Pt: Mn is 6: 4, if the amount of element X '(X' = Mo) is less than about 1 at%, the amount of element X '(X' = Mo) Is 0 at%, the exchange coupling magnetic field becomes larger.

When the composition ratio of Pt: Mn is 1:
In the case of 1, the amount of the element X ′ (X ′ = Mo) is about 7 at%.
If it is less than or equal to, the exchange coupling magnetic field becomes larger than when the amount of the element X ′ (X ′ = Mo) is 0 at%.

Further, the ratio of the composition ratio of Pt: Mn is
In the case of 4: 6, the amount of element X '(X' = Mo) is about 10
At% or less, the element X '(X' = Mo) content is 0a.
The exchange coupling magnetic field is larger than at t%.

Next, as the lower limit of the suitable content of the element X ′ (X ′ = Mo), the ratio of the composition ratio of Pt: Mn is as follows.
In the case of 6: 4, the amount of the element X ′ (X ′ = Mo) is about 0.5
When it is at%, the exchange coupling magnetic field becomes the largest,
Therefore, in the present invention, the amount of the element X ′ (X ′ = Mo) is set to 0.
0.2 at% smaller than 5 at% was set as the lower limit.

From the above experimental results, the present invention shows that the element X '
The preferred range of the composition ratio was 0.2 to 10 at%. A more preferable range is 0.5 to 5 in at%.

[0087]

According to the present invention described in detail above, the antiferromagnetic layer is made of an X ″ -Mn alloy (where X ″ is Pt, Pd,
Ir, Rh, Ru, or Os).
Compared with the case where an n-alloy or the like is used for the antiferromagnetic layer, the corrosion resistance can be improved, and a larger exchange anisotropic magnetic field can be obtained.

Alternatively, in the present invention, the element X '(where X' is Ne, Ar, Kr, Xe, Be, B, C, N,
Mg, Al, Si, P, Ti, V, Cr, Fe, Co,
Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, A
g, Cd, Ir, Sn, Hf, Ta, W, Re, Au,
Pb and one or more of the rare earth elements are converted to an X-Mn alloy film (where X is Pt, Pd,
A larger exchange anisotropic magnetic field can be obtained by forming a solid solution in the interstitial type or the substitution type in Ir, Rh, Ru, or Os). It has become.

As described above, by applying the exchange coupling film capable of obtaining a large exchange anisotropic magnetic field to the magnetoresistance effect element, the corrosion resistance can be improved, and the magnetoresistance effect element layer can be improved. The rate of change in resistance can be increased, and the reproduction characteristics can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a structure of a dual spin-valve thin film element according to an embodiment of the present invention, viewed from the ABS side.

FIG. 2 is a cross-sectional view of the thin-film magnetic head according to the present invention as viewed from a surface facing a recording medium;

FIG. 3 shows an antiferromagnetic layer formed of Pt—Mn—X ′ (X ′ = Ar)
A graph showing the relationship between the amount of the element X ′ (X ′ = Ar) and the lattice constant of the antiferromagnetic layer when formed by

FIG. 4 shows an antiferromagnetic layer formed of Pt—Mn—X ′ (X ′ = Ar)
A graph showing the relationship between the amount of the element X ′ (X ′ = Ar) and the exchange coupling magnetic field when formed by

FIG. 5 shows an antiferromagnetic layer formed of Pt—Mn—X ′ (X ′ = Mo)
A graph showing the relationship between the amount of the element X ′ (X ′ = Mo) and the lattice constant of the antiferromagnetic layer when formed by

FIG. 6 shows an antiferromagnetic layer formed of Pt—Mn—X ′ (X ′ = Mo)
A graph showing the relationship between the amount of the element X ′ (X ′ = Mo) and the exchange coupling magnetic field when formed by

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 free magnetic layer 2 nonmagnetic conductive layer 3 fixed magnetic layer 4 antiferromagnetic layer 5 hard bias layer 6 underlayer 7 protective layer 8 conductive layer 20 lower shield layer 21 lower gap layer 22 magnetoresistive element layer 23 upper gap layer 24 Upper shield layer

Continued on the front page (72) Inventor Kazuya Ominato 1-7 Yukitani Otsukacho, Ota-ku, Tokyo Alps Electric Co., Ltd. (72) Inventor Yutaka Yamamoto 1-7 Yukitani Otsukacho, Ota-ku, Tokyo Alps Electric Inside (72) Inventor Akihiro Makino Inside Alps Electric Co., Ltd., 1-7 Yukitani Otsuka-cho, Ota-ku, Tokyo

Claims (11)

[Claims] A non-magnetic conductive layer laminated above and below a free magnetic layer; a fixed magnetic layer positioned above one non-magnetic conductive layer and below another non-magnetic conductive layer; An antiferromagnetic layer in contact with the magnetic layer and below the other fixed magnetic layer to fix the magnetization direction of each fixed magnetic layer in a fixed direction by an exchange anisotropic magnetic field; and the magnetization direction of the free magnetic layer. And a bias layer that aligns the magnetization direction of the pinned magnetic layer with the magnetization direction of the pinned magnetic layer. The antiferromagnetic layer has X ″ -Mn (where X ″ is Pt,
X ″ -Mn that forms the antiferromagnetic layer located on one of the pinned magnetic layers, which is one or more of Pd, Ir, Rh, Ru, and Os). The composition ratio of X ″ in the alloy is at% and is 4%.
The composition ratio of X ″ of the X ″ -Mn alloy forming the antiferromagnetic layer located below the other pinned magnetic layer is at.
57. A magnetoresistive element having a range of 57. 2. The composition ratio of X ″ of an X ″ —Mn alloy forming the antiferromagnetic layer located on the one fixed magnetic layer is at% and is in a range of 50 to 56, The composition ratio of X ″ of the X ″ -Mn alloy forming the antiferromagnetic layer located under the other pinned magnetic layer is at%,
The magnetoresistance effect element according to claim 1, wherein the value is within the range of 55. 3. X ″-used as the antiferromagnetic layer
3. The magnetoresistive element according to claim 1, wherein the element X ″ of the Mn alloy is Pt. 4. A nonmagnetic conductive layer laminated above and below a free magnetic layer, a fixed magnetic layer located above one nonmagnetic conductive layer and below another nonmagnetic conductive layer, and one of the fixed magnetic layers An antiferromagnetic layer in contact with the magnetic layer and below the other fixed magnetic layer to fix the magnetization direction of each fixed magnetic layer in a fixed direction by an exchange anisotropic magnetic field; and the magnetization direction of the free magnetic layer. X-Mn-X 'alloy (where X is any one of Pt, Pd, Ir, Rh, Ru, Ru and Os). Or two or more elements, and the element X ′ is Ne, Ar, Kr, Xe, Be, B, C, N,
Mg, Al, Si, P, Ti, V, Cr, Fe, Co,
Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, A
g, Cd, Ir, Sn, Hf, Ta, W, Re, Au,
An X-Mn-X 'alloy that forms the antiferromagnetic layer located on one of the pinned magnetic layers. The composition ratio of X + X ′ is at
% In the range of 47 to 57, and the composition ratio of X + X 'of the X-Mn-X' alloy forming the antiferromagnetic layer located under the other fixed magnetic layer is at%
The magnetoresistive element according to any one of the preceding claims, wherein the magnetoresistance effect element ranges from 44 to 57. 5. X + X ′ of an X—Mn—X ′ alloy forming said antiferromagnetic layer located on said one pinned magnetic layer
Is in the range of 50 to 56, and the composition ratio of X + X ′ of the X—Mn—X ′ alloy forming the antiferromagnetic layer located below the other pinned magnetic layer is at%. %
The magnetoresistive element according to claim 4, wherein the value is in the range of 46 to 55. 6. The element X ′ is Ne, Ar, Kr, X
The magnetoresistance effect element according to claim 4, wherein the element is one or more of e. 7. XM used as said antiferromagnetic layer
7. The magnetoresistive element according to claim 4, wherein the element X of the nX 'alloy is Pt. 8. The composition ratio of said element X 'is at%,
The magnetoresistive element according to any one of claims 4 to 7, which is within a range of 2 to 10. 9. The composition ratio of the element X ′ is at%, and
9. The magnetoresistive element according to claim 8, wherein the value is in the range of 5 to 5. 10. X-rays used as the antiferromagnetic layer
The magnetoresistive element according to any one of claims 4 to 9, wherein the Mn-X 'alloy is formed by a sputtering method. 11. A thin-film magnetic head, wherein a shield layer is formed above and below a magnetoresistive element according to claim 1 with a gap layer interposed therebetween.