JP2000276710A - Magnetoresistive element, magnetoresistive head, and hard disk device using magnetoresistive head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable magnetoresistive element and head to have a large MR ratio by successively laminating a nonmagnetic high-resistance layer, a first ferromagnetic layer, a first nonmagnetic layer, a second ferromagnetic layer and an antiferromagnetic layer. SOLUTION: The second ferromagnetic layer 5 receives alternating bias magnetic fields from the antiferromagnetic layer and the magnetization direction is fixed in one direction. On the other hand, since the first ferromagnetic layer 3 formed via the nonmagnetic layer 4 freely changes the magnetization direction according to the magnetic fields from outside, the relative angle of the first ferromagnetic layer 3 and the second ferromagnetic layer 5 changes and electric resistance (magnetic reluctance) changes. Current flows between the first ferromagnetic layer 3 and the antiferromagnetic layer 7 and if the antiferromagnetic layer 8 is formed of suitable material, the smoothness of an atom level is embodied at the boundary S1 between the antiferromagnetic layer 8 and the first ferromagnetic layer 3 and the MR ratio increases. Al2O3, AlN, SiO2, etc., and used as the material of the antiferromagnetic layer 8 and the film thickness thereof is preferably specified between 0.4 and 20 nm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive element which causes a large magnetoresistance change in a low magnetic field, a magnetoresistive head and a magnetoresistive effect head formed by using the element. The present invention relates to a hard disk drive using a head.

[0002]

2. Description of the Related Art Conventionally, a magnetoresistive sensor (hereinafter, referred to as an MR sensor) using a magnetoresistive effect element (hereinafter, also referred to as an MR element) and a magnetoresistive head (hereinafter, referred to as an MR head) have been developed and put into practical use. For the magnetic material, a permalloy of Ni _0.8 Fe _0.2 or a Ni _0.8 Co _0.2 alloy film is mainly used. In the case of these magnetoresistive effect materials, the magnetoresistance ratio (hereinafter, referred to as MR ratio) is about 2%, and to obtain a more sensitive magnetoresistive element, a material having a higher MR ratio is required. In recent years, antiferromagnetic coupling has been performed via a non-magnetic thin film of metal such as Cr or Ru [Fe / C
r], [Co / Ru] artificial lattice film has a strong magnetic field (1 to 10 k
Oe) was found to show a large resistance change of about 100% (giant magnetoresistance effect) (Physical Review).
Letter 61, p. 2472 (1988);
P. 304 (1990) (Physical Review)
w Letter Vol. 61, p2472, 198
8; 64, p2304, 1990)).

However, these artificial lattice films require a magnetic field of several kOe to several tens kOe to obtain a large MR change, and are not practical for applications such as a magnetic head.

In order to operate with a small applied magnetic field, an antiferromagnetic material, Fe—Mn, is replaced with Ni—Fe / Cu / Ni—F
e, a spin valve type has been proposed (Journal of Magnetics and Magnetic Materials 93, p. 101 (1991)).
(Journal of Magnetism and
Magnetic Materials 93, p10
1, 1991)).

FIG. 11 shows the structure of a conventional spin valve film 310. The conventional spin-valve film 310 is formed on the substrate 1 directly or via the base film 2 through the first ferromagnetic layer 3,
The nonmagnetic film 4, the second ferromagnetic film 5, and the metal antiferromagnetic material 7 are sequentially laminated. In this type of spin valve film, the ferromagnetic film (pin layer) 5 in contact with the antiferromagnetic material 7 is given unidirectional anisotropy by exchange coupling,
The magnetization direction is fixed in one direction. On the other hand, in the ferromagnetic layer 3 (free layer) provided with the pinned layer 5 and the nonmagnetic layer 4 interposed therebetween, the magnetization direction can be relatively freely rotated with respect to an externally applied signal magnetic field. Layer 5 and free layer 3
, The relative magnetization direction changes, and the electrical resistance changes. This type of MR material has a small operating magnetic field and good linearity, but has a small MR ratio of about 2%,
There were problems such as the problem of corrosion resistance of the film, and the fact that the Neel temperature of the Fe-Mn thin film was low, so that the temperature dependence of device characteristics was large.

[0006] In order to improve such a defect of the Fe-Mn film, various kinds of metal antiferromagnetic materials such as Pt-Mn and Ir-Mn have been proposed. These have excellent temperature characteristics compared to Fe-Mn, and are relatively resistant to heat application in the magnetic head manufacturing process, and should be used without deteriorating the characteristics even when the temperature rises during operation as a head. Can be. However, the spin valve film using such a metal antiferromagnetic material has a low MR ratio of at most about 10%,
It is thought that it will not be compatible with future high-density magnetic recording heads.

Further, as one of means for increasing the MR ratio of the spin valve film, a metal having a low specific resistance is further provided by a low resistance back layer provided on the back of the spin valve film to form Cu / Ni.
A structure having a structure of -Fe / Cu / Ni-Fe / Fe-Mn has also been proposed (US Pat. No. 5,422,571). This is an attempt to increase the MR ratio by increasing the mean free path of electrons of a specific spin.

The conventional spin-valve type MR element has an excellent magnetic field sensitivity, but has a problem that the MR ratio is low. The effect of improving the MR ratio by the low-resistance back layer was not sufficient. This is considered because electrons are easily diffused and scattered on the surface of the spin-valve MR element because the film thickness is small.

This will be described in more detail as follows.

Originally, the giant magnetoresistive effect was caused by the magnetic layer /
This is due to the spin-dependent scattering of electrons at the interface of the nonmagnetic layer. Therefore, in order to increase the probability of occurrence of this scattering, it is important to reduce the probability of scattering independent of the spin direction and lengthen the mean free path of electrons. In the spin valve film, the number of times of lamination of the magnetic layer / non-magnetic layer is small. Therefore, the thickness of the spin valve film is, for example, 20-5.
The thickness is about 0 nm, which is generally smaller than that of a giant magnetoresistance effect film of an antiferromagnetic coupling type. Therefore, the probability that electrons are scattered on the film surface is high, and the mean free path of the electrons is short. This is the main reason why the MR ratio of the spin valve film is low.

Normally, the surface of a thin film has irregularities when viewed at a level of several angstroms, which is a level of a conduction electron wavelength (Fermi wavelength). In this case, the conduction electrons undergo inelastic scattering (diffuse scattering) on the surface. In general,
In the case of diffusion scattering, the spin direction of electrons is not maintained.

In order to improve the decrease in the MR ratio due to the diffusion scattering of electrons on the film surface, a specular reflection type spin valve film having an ultra-smooth film surface has been proposed.

As a mirror reflection type spin valve film proposed by the applicant, a metal reflection film type (for example, Japanese Patent Application No. 9-3268) in which a metal film which tends to be super smooth is formed on the surface.
22, JP-A-11-8424) and a mold using an oxide antiferromagnetic material (for example, Japanese Patent Application No. 10-27618).
No. 1).

As shown in FIG. 12, the structure of a spin valve film using a metal reflection film is the structure of a normal spin valve film 320, that is, an antiferromagnetic layer 7, a pinned layer 5, a nonmagnetic layer 4,
In addition to the free layer 3, a metal reflection film layer 9 is further formed. A current, that is, conduction electrons flow from the metal reflection film layer 9 to the space between the antiferromagnetic material layer 7 (the pinned layer 5 when the antiferromagnetic material layer is an oxide). If it is smooth, the conduction electrons are specularly reflected on the surface of the metal reflection film, and the MR ratio increases as compared with the case where the metal reflection layer is not provided.

A typical structure using an oxide antiferromagnetic material is a spin valve film 33 as shown in FIG.
No. 0, that is, a structure in which an oxide antiferromagnetic layer 7, a pinned layer 5, a nonmagnetic layer 4, and a free layer 3 are sequentially stacked on a substrate 1 with an underlayer 2 interposed therebetween. The oxide antiferromagnetic layer 7 usually has a high resistance, and no current flows. That is, the antiferromagnetic material is F
When the antiferromagnetic layer is made of a metal such as e-Mn, the current flows between the free layer 3 and the antiferromagnetic layer 7, but when the antiferromagnetic layer is an oxide, the current flows through the free layer. It flows between 3 and the second ferromagnetic layer 5. In this case, if the interface between the oxide antiferromagnetic layer 7 and the pinned layer 5 is very smooth,
The conduction electrons are specularly reflected, and the MR ratio is increased as compared with the case where a metal antiferromagnetic material is used.

An oxide antiferromagnetic material used for this type of spin valve film is NiO (Physical Review B, Vol. 53, pp. 9108 (1996) (Phy).
physical Review B Vol. 53, p91
08, 1996-II), α-Fe ₂ O _{3 and the} like (Japan
es Journal of applied Ph
ysics Vol. 37, p5984, 1998)
It has been proposed to use In this case, a large MR ratio of 10% or more is reported.

[0017]

The spin valve type MR element using the conventional metal antiferromagnetic material does not have a sufficiently high MR ratio. In addition, even in a spin valve film utilizing a specular reflection effect to improve this, conventionally, the increase of the MR ratio has been insufficient. When a metal reflective film is used, the MR ratio is lowered due to the change of the surface due to oxidation or the like, and the MR ratio is reduced depending on the protective layer for preventing this.
The ratio was insufficiently increased, or the MR ratio was conversely reduced.

When an oxide antiferromagnetic material is used, a large MR ratio is obtained. For example, in FIG. 13, the surface of the conductive layer opposite to the oxide antiferromagnetic material is a free layer 3. Thus, the effect of reflecting electrons was insufficient, and the increase in MR ratio was not sufficient.

The present invention has been made to solve such a problem. An object of the present invention is to provide a magnetoresistive element, a magnetoresistive head, and a hard disk drive using the magnetoresistive head, which exhibit a large MR ratio.

[0020]

According to the present invention, there is provided a magnetoresistive element comprising a nonmagnetic high resistance layer, a first ferromagnetic layer, a first nonmagnetic layer, a second ferromagnetic layer, and an antiferromagnetic layer. Are sequentially laminated, whereby the object is achieved.

The non-magnetic high resistance layer may have a property of easily reflecting conduction electrons while maintaining the direction of electron spin.

The thickness of the non-magnetic high resistance layer is 0.4 nm.
It may be not less than 20 nm.

The thickness of the non-magnetic high resistance layer is 0.4 nm.
It may be not less than 2 nm.

[0024] The non-magnetic high resistance layer may contain an oxide of Al.

The non-magnetic high-resistance layer may have a reflective surface in contact with the metal reflective film layer, and at least a part of the reflective surface may be smooth when viewed on a angstrom level.

At least 10% or more of the reflecting surface has:
It may be a smooth surface with irregularities of 0.5 nm or less.

The antiferromagnetic layer may contain an oxide.

The oxide may contain α-Fe ₂ O ₃ .

The oxide may include NiO.

The non-magnetic layer contains Cu, and at least one of the first ferromagnetic layer and the second ferromagnetic layer includes:
It may include at least one of Fe, Ni, Co, and alloys thereof.

[0031] The second ferromagnetic layer further includes a second non-magnetic layer, and a third ferromagnetic layer and a fourth ferromagnetic layer laminated via the second non-magnetic layer. May be.

At least one of the third ferromagnetic layer and the fourth ferromagnetic layer contains at least one of Co and a Co—Fe alloy, and the second nonmagnetic layer contains Ru and Ir
May be included.

Another magnetoresistive element according to the present invention comprises a high resistance layer, a metal reflection film layer, a first ferromagnetic layer, a first nonmagnetic layer,
The second ferromagnetic layer and the antiferromagnetic layer are sequentially stacked, and the above object is achieved.

The high-resistance layer may have a property of easily reflecting conduction electrons while maintaining the direction of electron spin.

The metal reflection film layer may contain at least one of Au and Ag as a main component.

The thickness of the high resistance layer is 0.4 nm or more and 2
It may be 0 nm or less.

The thickness of the high resistance layer is 0.4 nm or more and 2
nm or less.

The high resistance layer may include an oxide of Al.

[0039] The high resistance layer may have a reflective surface in contact with the first ferromagnetic layer, and at least a portion of the reflective surface may be smooth when viewed in Angstroms.

At least 10% or more of the reflecting surface is
It may be a smooth surface with irregularities of 0.5 nm or less.

The high resistance layer may include α-Fe ₂ O ₃ .

[0042] The antiferromagnetic layer may contain an oxide.

The oxide may include α-Fe ₂ O ₃ .

The oxide may contain NiO.

The first nonmagnetic layer contains Cu, and at least one of the first ferromagnetic layer and the second ferromagnetic layer contains at least one of Fe, Ni, Co, and an alloy thereof. One may be included.

The second ferromagnetic layer further includes a second non-magnetic layer, and a third ferromagnetic layer and a fourth ferromagnetic layer stacked with the second non-magnetic layer interposed therebetween. May be.

At least one of the third ferromagnetic layer and the fourth ferromagnetic layer contains at least one of Co and a Co—Fe alloy, and the second nonmagnetic layer contains Ru and Ir
May be included.

[0048] A second non-magnetic layer may be further laminated between the metal reflection film layer and the first ferromagnetic layer.

In the magnetoresistive head according to the present invention, a nonmagnetic high resistance layer, a first ferromagnetic layer, a first nonmagnetic layer, a second ferromagnetic layer, and an antiferromagnetic layer are sequentially laminated. A magnetoresistive element having the above configuration, a bias application unit for controlling the magnetic domain of the first ferromagnetic material, and a recording unit, thereby achieving the above object.

[0050] The second ferromagnetic layer further includes a second non-magnetic layer, and a third ferromagnetic layer and a fourth ferromagnetic layer laminated with the second non-magnetic layer interposed therebetween. May be.

Another magnetoresistive head according to the present invention comprises a high resistance layer, a metal reflection film layer, a first ferromagnetic layer, a first nonmagnetic layer, a second ferromagnetic layer, and an antiferromagnetic layer. Are sequentially stacked, a bias application unit for controlling the magnetic domain of the first ferromagnetic material, and a recording unit, thereby achieving the object described above.

[0052] A second non-magnetic layer may be further laminated between the metal reflective film layer and the first ferromagnetic layer.

The hard disk drive of the present invention is a hard disk drive for recording and reproducing information on a disk by using a magnetoresistive head, and the hard disk device holds the magnetoresistive head and the magnetoresistive head. A magnetoresistive head support mechanism comprising: a slider that drives the magnetoresistive head; and a driving unit that tracks the magnetoresistive head via the magnetoresistive head support mechanism. A magnetoresistive element having a structure in which a high resistance layer, a first ferromagnetic layer, a first nonmagnetic layer, a second ferromagnetic layer, and an antiferromagnetic layer are sequentially stacked; A bias applying unit for controlling the magnetic domain of the body and a recording unit are provided, whereby the object is achieved.

Another hard disk drive of the present invention is a hard disk drive for recording and reproducing information on a disk by using a magnetoresistive head, wherein the hard disk drive comprises the magnetoresistive head and the magnetoresistive head. A magnetoresistive head support mechanism comprising a slider for holding the magnetic field, and a driving unit for tracking the magnetoresistive head via the magnetoresistive head support mechanism, wherein the magnetoresistive head comprises: A high resistance layer, a metal reflection film layer, a first ferromagnetic layer, a first nonmagnetic layer,
A magnetoresistive element having a configuration in which a second ferromagnetic layer and an antiferromagnetic layer are sequentially stacked; a bias application unit for controlling the magnetic domain of the first ferromagnetic material; and a recording unit. This achieves the above object.

[0055]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a magnetoresistive element according to the present invention,
A magnetoresistive head and a hard disk drive using the magnetoresistive head will be described with reference to the drawings.

FIG. 1 shows an example of the configuration of the magnetoresistive element of the present invention. An MR element 100A shown in FIG. 1A includes a non-magnetic high-resistance layer 8, a first ferromagnetic layer 3, a non-magnetic layer 4, and a second ferromagnetic layer 8 directly on a substrate 1 or via an underlayer 2. 5, an antiferromagnetic layer 7 is sequentially laminated.
The operation of the magnetoresistive element of the present invention is basically the same as that of the spin valve film 310 shown in FIG. However, since the nonmagnetic high-resistance layer 8 is further formed below the first ferromagnetic layer 3, the MR ratio is increased as compared with the conventional case.

The operation of the multilayer film shown in FIG. 1A as a spin-valve magnetoresistive element will be described as follows. The second ferromagnetic layer 5 receives an exchange bias magnetic field from the antiferromagnetic layer 7 and the magnetization direction is fixed in one direction. On the other hand, the first ferromagnetic layer 3 formed via the non-magnetic layer 4
Changes the magnetization direction relatively freely in response to an external magnetic field, the relative angle between the magnetization directions of the first ferromagnetic layer (free layer) 3 and the second ferromagnetic layer (pinned layer) 5 is changed. And the electrical resistance (magnetic resistance) changes. As an MR sensor, a resistance change caused by an external magnetic field can be read as an electric signal.

FIG. 1A shows a case where the non-magnetic high-resistance layer 8 is laminated in order, but conversely, as shown in FIG. 1B, the anti-ferromagnetic layer 7 is laminated. The present invention is also effective.

The reason why the magnetoresistive elements 100A and 100B of the present invention as shown in FIG. 1 exhibit a higher MR ratio than the conventional magnetoresistive elements is considered as follows. That is, in the MR element 310 shown in FIG. 11, conduction electrons (current) flow between the metal antiferromagnetic layer 7 and the underlayer 2 (usually a metal such as Ta is used for the underlayer). When an ordinary material is used, the interface between the substrate 1 and the underlayer 2 or the surface of the metal antiferromagnetic layer 7 has no atomic level smoothness, so that the electrons are diffusely scattered here and the spin information of the electrons is lost. Therefore, the MR ratio becomes low.

On the other hand, in the case of FIG. 1A of the present invention, the electric current, that is, the conduction electrons, is applied to the first ferromagnetic layer 3 and the antiferromagnetic layer 7 (or the second ferromagnetic layer 7). Flow between 5).
At this time, if the non-magnetic high-resistance layer 8 is formed of an appropriate material by an appropriate method, the interface S1 between the non-magnetic high-resistance layer 8 and the first ferromagnetic layer 3 achieves atomic level smoothness, and the MR ratio Increase.

As the high resistance layer 8 in FIG. 1A, a non-magnetic high resistance layer is preferable. It is not desirable to use a ferromagnetic or antiferromagnetic material for the high-resistance layer 8 because it is magnetically coupled to the first ferromagnetic layer 3 and makes it difficult to rotate the magnetization of the first ferromagnetic layer 3. The material of the non-magnetic high resistance layer 8 is Al ₂ O ₃ , Al
Various non-magnetic high resistance materials such as N and SiO ₂ are suitable. Particularly, Al ₂ O ₃ is preferable. At this time, if the film thickness is too small, the insulating effect is too low.
Desirably, a film thickness of 0.8 nm or more is required. However, if the thickness is too large, the surface roughness increases, and the mirror reflection effect of electrons decreases. Therefore, the thickness is preferably 20 nm or less, more preferably 2 nm or less.

In order to obtain a large MR ratio using the high-resistance layer, for example, in FIG.
It is necessary to keep the probability of specular reflection high at the interface S1 between the magnetic layer 3 and the ferromagnetic layer 3. The condition for specular reflection at the interface S1 is that the interface S1 between the nonmagnetic high-resistance layer 8 and the first ferromagnetic layer 3 needs to be smooth when viewed from the wavelength (several angstrom) of conduction electrons.

When the smoothness of the interface S1 between the nonmagnetic high-resistance layer 8 and the first ferromagnetic layer 3 is evaluated, it is desirable that the smoothness of the interface S1 or the plane of the nonmagnetic high-resistance layer 8 be evaluated. If this is difficult, the evaluation may be made based on the smoothness of the multilayer film surface.

As for the smoothness of the surface of the multilayer film, it is satisfactory if the entire surface is completely smooth. It should just be done. Specifically, a portion where a smooth surface with irregularities of 0.5 nm or less is formed in a region of 10 nm × 10 nm or more accounts for approximately 10% or more of the entire surface, preferably 20% or more.
% Is required.

Next, the material of the antiferromagnetic layer 7 is a metal film.
When used, Fe-Mn, Ni-Mn, Pd-Mn,
Pt-Mn, Ir-Mn, Cr-Al, Cr-Mn-P
t, Fe-Mn-Rh, Pd-Pt-Mn, Ru-Rh
-Films of Mn, Mn-Ru, Cr-Al, etc. are excellent.
Among them, from the viewpoint of corrosion resistance and thermal stability, Ni-M
n, Ir-Mn and Pt-Mn are excellent. Especially Pt-
Mn is excellent. Pt _ZMn_1-ZAs a suitable composition of the membrane
Is preferably an atomic composition ratio of 0.45 ≦ z ≦ 0.55. Money
The thickness of the antiferromagnetic material 7 depends on the magnetization pinning effect of the fixed layer.
To increase the (bias effect), at least 5n
A film thickness of m or more is required. More preferably, 10 nm or less
Is necessary. However, if it becomes too thick, the wavelength will be shortened in the future
30 nm or less, more preferably
It is desirable that the thickness be 20 nm or less. Metal antiferromagnet 7
The MR ratio is lower than the oxide antiferromagnetic material described below
Has excellent thermal stability.

When an oxide antiferromagnetic material is used as the metal antiferromagnetic material 7, electrons are also specularly reflected between the oxide antiferromagnetic material 7 and the second ferromagnetic layer 5, and the MR ratio is reduced. Is further increased. This is the same as the above-described conventional example shown in FIG.

FIG. 1B of the present invention corresponds to FIG.
The difference from the third ferromagnetic layer 3 is that not only does specular reflection occur between the oxide antiferromagnetic material 7 and the second ferromagnetic material 5 but also between the nonmagnetic high-resistance layer 8 and the first ferromagnetic layer 3. However, a specular reflection effect is caused, and electrons are specularly reflected on both surfaces between the first ferromagnetic layer 3 and the second ferromagnetic layer 5, so that the case of FIG. The MR ratio further increases as compared with. NiO, CoO, α-
Fe ₂ O ₃ films and the like are excellent, and among them, α-Fe ₂ O ₃ , Ni
O films exhibit excellent properties. The thickness of the oxide antiferromagnetic material is required to be 5 nm or more because the thinner the thickness, the lower the bias effect. On the other hand, if the thickness is too large, there is a problem that the overall film thickness becomes large.

As the second ferromagnetic layer 5, Co or C
By using an o _1-x Fe _x alloy (0 <x ≦ 0.5, x is an atomic composition ratio) or a Co—Ni—Fe alloy, a large MR ratio can be obtained. The Co _1-x Fe _x alloy has a large spin-dependent scattering, particularly when Cu is used as the non-magnetic film, resulting in a large MR ratio. Second ferromagnetic layer 5
If the film thickness is too small, the MR ratio decreases, and if it is too large, the exchange bias magnetic field decreases. Therefore, it is desirable that the film thickness be 1 nm or more and 3 nm or less, more preferably 1.5 nm or more and 2.5 nm or less.

For the first ferromagnetic layer 3, soft magnetic characteristics are important, and Ni—Fe, Ni—Co—Fe, or a Co—Fe alloy is suitable. The atomic composition ratio of the Ni—Co—Fe film is as follows: Ni _X Co _Y Fe _Z 0.6 ≦ x ≦ 0.9 0 ≦ y ≦ 0.4 0 ≦ z ≦ 0.3 Ni-rich soft magnetic film Or Ni _{X '} Co _Y'
It is desirable to use a Co-rich film satisfying FeZ _' 0 ≦ x ≦ 0.4 0.2 ≦ y ≦ 0.95 0 ≦ z ≦ 0.5. Films having these compositions have low magnetostriction characteristics (1 × 10 −5) required for sensors and MR heads. Other materials for the first ferromagnetic layer 3 include Co—Mn—B and Co—F.
An amorphous film such as e-B, Co-Nb-Zr, or Co-Nb-B may be used.

The thickness of the first ferromagnetic layer 3 is preferably 1 nm or more and 10 nm or less. When the film thickness is thick, M
The R ratio decreases, but if it is too thin, the soft magnetic properties deteriorate.
More preferably, the thickness is 1.5 nm or more and 5 nm or less.

In order to further increase the MR ratio, Co or a Co—Fe alloy may be inserted as an interface magnetic layer at the interface between the first and second ferromagnetic layers 3 and 5 and the nonmagnetic layer 4. It is valid. When the thickness of the interface magnetic layer is large, the magnetic field sensitivity of the MR ratio decreases. Therefore, the thickness of the interface magnetic layer needs to be 2 nm or less, preferably 1 nm or less. In order for this interfacial magnetic layer to work effectively, at least 0.4 n
A film thickness of m or more is required.

The nonmagnetic layer 4 is made of Cu, Ag, Au,
Although there are Ru and the like, Cu is particularly excellent. Non-magnetic layer 4
Is required to be at least 0.8 nm or more, preferably 1.8 nm or more in order to weaken the interaction between the magnetic layers. When the thickness of the non-magnetic layer 4 is increased, the MR ratio is reduced.
nm or less.

The underlayer 2 must be carefully selected because it affects the orientation, crystallinity, soft magnetic characteristics and the like of the entire magnetoresistive element. Usually, Ta is often used. However, if Cu, Ag, Au, or an alloy thereof is further used on Ta, it is useful for improving the soft magnetic characteristics of the first ferromagnetic layer 3.

The present invention is also effective for the substrate 1 such as Si, glass, sapphire, MgO, and Al ₂ O ₃ —TiC substrate usually used for a magnetoresistive head.

In order to further increase the bias magnetic field applied to the pinned layer, in other words, to stabilize the magnetization direction of the pinned layer, the second ferromagnetic layer 5 is formed of a ferromagnetic layer / non-magnetic layer / ferromagnetic layer. It is also effective to use an indirect exchange coupling membrane consisting of three layers. If an appropriate material and thickness are selected for the material of the ferromagnetic layer and the nonmagnetic layer, a large antiferromagnetic coupling occurs between the two ferromagnetic layers, and this indirect exchange coupling film forms a stronger pinned layer. Can be stabilized. This indirect exchange coupling film is obtained by inserting an appropriate nonmagnetic layer between a pair of ferromagnetic layers.

Materials suitable for the ferromagnetic layer are Co, Co-
Fe, Co-Fe-Ni alloy, etc., especially Co, Co
-Fe alloy is excellent. As the intermediate nonmagnetic layer, Ru, Ir or the like is suitable, and Ru is particularly preferable. The thickness of the ferromagnetic film is required to be at least 1 nm or more.
nm or less. At this time, it is better that the thicknesses of the ferromagnetic films differ by at least 0.5 nm or more than the same. The thickness of the nonmagnetic layer is 0.3 nm or more and 1.2 nm or less, more preferably 0.4 nm or more and 0.1 nm or more.
9 nm or less is appropriate.

While the example of FIG. 1 has been described above, FIG. 2 shows another example of the configuration of the present invention. In FIG. 2, in order to enhance the effect of the high resistance layer 8a, a metal reflection film layer 9 for further enhancing the mirror reflection effect of electrons is provided between the high resistance layer 8a and the first ferromagnetic layer 3.

The high resistance layer 8a in FIG. 2 may be a non-magnetic high resistance material similar to the high resistance layer 8 in FIG. 1 or a magnetic material. Among the magnetic materials, the antiferromagnetic material need not have an extra leakage magnetic flux. As a high-resistance antiferromagnetic material, α
-Fe ₂ O _3, NiO good oxide antiferromagnetic body such as a membrane. Among them, the α-Fe ₂ O ₃ film is excellent. Such a film has a smooth surface and tends to cause an electron mirror reflection effect.

As the metal reflection film layer 9, if a material whose surface is likely to be super-smooth is introduced, the interface S at which electrons are reflected is used.
2, the probability of specular reflection of electrons increases, and the MR ratio increases. As a material of the metal reflection film layer 9, Au, Ag, or the like is appropriate. The film thickness must be at least 0.4 nm or more, and if it is too thick, the shunt effect lowers the resistance and MR ratio.
Should be:

It is also effective to introduce a Cu layer between the metal reflection film layer 9 and the first ferromagnetic layer 3 in order to further enhance the effect of the metal reflection film layer 9.

The above-mentioned layers may be formed in the following manner.
It can be manufactured by a method such as a sputtering method or an evaporation method.
DC sputtering, RF sputtering
There are a sputtering method, an ion beam sputtering method, and the like, and any method can produce the magnetoresistive elements 200A and 200B of the present invention.

As a method of forming the high resistance layer 8a, in the case of oxides and nitrides, a reactive sputtering method is also effective.
This is a method of sputtering an Al target using a mixed gas of Ar gas and oxygen gas, for example, when producing an Al ₂ O ₃ film. In this method, usually Al ₂
A with better quality than the method of sputtering O ₃ target
It is known that an l ₂ O ₃ film can be produced. In the case of oxide, a method of forming an oxide film by forming a metal film and then oxidizing the metal film by a plasma oxidation method is also known as a method of obtaining a high-quality oxide film.

A magnetoresistive head can be constructed using the magnetoresistive elements 100A, 100B, 200A or 200B of the present invention as described above. FIG. 4 shows an example of the configuration of the MR head. FIG. 3 is a view of FIG. 4 as viewed in the direction of arrow A, and FIG. 5 shows a cross section taken along a plane indicated by a dotted line B. Hereinafter, description will be made mainly with reference to FIG.

In FIG. 3, the MR element portion 109 is configured to be sandwiched between the upper and lower shield caps 14 and 11. Al ₂ O ₃ ,
An insulating film such as AlN or SiO ₂ is used. Further outside the shield caps 11 and 14 are upper and lower shields 10 and 15, which are made of Ni-Fe, Fe-Al-S.
i, a soft magnetic film such as a Co-Nb-Zr alloy is used.
In order to control the magnetic domain of the first ferromagnetic layer (free layer) 3 of the MR element, a bias magnetic field is applied by a hard bias unit 12 such as a Co-Pt alloy.

Here, the case where a hard film is used as the bias application method has been described, but the same applies to the case where an antiferromagnetic material such as Fe-Mn is used. MR element part 1
09 is the shield 1 by the shield caps 11 and 14.
It is insulated from 0, 15, etc., and reads a resistance change of the MR element section 109 by flowing a current through the lead section 13.

Since the MR head is a read-only head, it is usually used in combination with an inductive head for writing. FIG. 6 shows not only the reproducing head section 32 but also the write head section 31. FIG. 6 shows a case where a write head portion is further formed in FIG. As the write head, there is an upper recording core 16 formed on the upper shield 15 via a recording gap 40.

FIGS. 3 and 6 illustrate a conventional MR head structure using an abutted junction. However, as the track is narrowed by increasing the density, the track width 41 can be more precisely regulated.
The one using the overlay structure shown in FIG. 7 is also effective.

Next, the recording / reproducing mechanism of the MR head will be described with reference to FIG. As shown in FIG. 5, at the time of recording, the magnetic flux generated by the current flowing through the coil 17 leaks from between the upper core 16 and the upper shield 15 and can be recorded on the magnetic disk 21. Head 30
Travels in the direction of arrow c relative to the disk 21. By reversing the current flowing through the coil 17,
The direction 23 of the recording magnetization can be reversed. Also,
Since the recording length 22 becomes shorter as the recording density increases, the recording cap length 19 must be reduced accordingly.

For reproduction, the magnetic flux 24 leaking from the recording magnetized portion of the magnetic disk 21 acts on the MR element portion 109 sandwiched between the shields 10 and 15 to change the resistance of the MR element. Since a current flows through the MR element section 109 via the lead section 13, a change in resistance can be read as a change in voltage (output).

In consideration of the future increase in the density of hard disk drives, it is necessary to shorten the recording wavelength. For this purpose, it is necessary to reduce the distance d between the shields (distance 18 in FIG. 5) shown in FIG. is there. For that purpose, as is clear from FIG. 5, it is necessary to make the MR element section 109 thin.
It is desirable that the film thickness of the MR element portion 109 be as small as possible.
It should be less than 50 nm, preferably less than 30 nm.

In the MR element section 109, the axis of easy magnetization of the first ferromagnetic film (free layer) 3 shown in FIG. 1 is set so as to suppress the occurrence of Barkhausen noise during the magnetization reversal of the soft magnetic film. It is preferable to be configured so as to be substantially perpendicular to the direction of the signal magnetic field to be detected. At this time, in order to cause a linear output change, the magnetization direction of the second ferromagnetic layer needs to be fixed in a direction perpendicular to the free layer in the film plane.

In the above description, the shield type MR head has been described. However, if the density becomes higher in the future, the insulating films 14 and 11 and the MR element portion 109 are formed in the shield gap 18.
Therefore, yoke type MR heads such as a vertical type MR head have been studied. Again, in this case,
The present invention is effective.

FIG. 9 is a side view of a hard disk drive 110 using the MR head according to the present embodiment.
0 is a plan view thereof.

The hard disk drive 110 includes a slider 120 for holding the MR head described in the present embodiment,
The head includes a head support mechanism 130 that supports the slider, an actuator 114 that tracks the MR head via the head support mechanism 130, and a disk drive motor 112 that rotationally drives a disk 116. Head support mechanism 1
30 includes an arm 122 and a suspension 124.

The disk drive motor 112
16 is rotated at a predetermined speed. Actuator 11
4 moves the slider 120 holding the MR head radially across the surface of the disk 116 so that the MR head can access a predetermined data track on the disk 116. The actuator 114 is typically a linear or rotary voice coil motor.

The slider 120 holding the MR head is
For example, an air bearing slider. In this case,
The slider 120 is used to activate the hard disk drive 110.
During the stop operation, the disk contacts the surface of the disk 116. At the time of the information recording / reproducing operation of the hard disk device 110, the slider 120
The air bearing formed between the disk 11
6 is maintained on the surface. The MR head held by the slider 120 records and reproduces information on the disk 116.

[0097]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetoresistive element and a magnetoresistive head according to the present invention will be described below using specific examples.

[0098] using a sputtering apparatus (Example 1) multi-chamber multiple, as a _{target, Ta, NiO, Ni 0. 8} Fe
_0.2 , Pt _0.45 Mn _0.55 , α-Fe ₂ O ₃ , Co, Cu,
Using a sputtering apparatus equipped with Al ₂ O ₃ , the inside of the vacuum chamber was evacuated to 1 × 10 −8 Torr or less, and then a sputtering method was used on a glass substrate while flowing Ar gas at about 0.8 mTorr. Thus, an MR element 100A having the configuration shown in FIG. As a cathode, Al ₂ O ₃ , NiO, rf in the case of α-Fe ₂ O ₃ film
A cathode was used, otherwise a DC cathode was used. Hereinafter, the thickness in parentheses indicates the film thickness in nm. The alloy composition is indicated by the composition of the target.

Al: Ta (5) / Al ₂ O ₃ (t) / Ni
_0.80 Fe _0.20 (5) / Co (1) / Cu (2.2) / C
o (2) / Pt _0.45 Mn _0.55 (20) / Ta (5) The formed MR element is subjected to a magnetic field of 200 kA / m in a vacuum.
Heat treatment was performed at 80C for 2 hours.

The characteristics of the MR element manufactured in this manner were measured at room temperature by a DC four-terminal method at a maximum of 400 kA / m (5000).
Evaluation was performed by applying a magnetic field of Oe). Table 1 shows the results. In Table 1, Hp means, as shown in FIG. 8, a strong magnetic field once applied in the negative direction to align the magnetization directions of the free layer and the pinned layer (a), and then the magnetic field is gradually increased. In the process (c) in which only the free layer is inverted and the MR ratio is maximized in (b) and the pinned layer is also inverted and the MR ratio is reduced, the MR ratio becomes half that in the state of (b). Let Hp be the applied magnetic field.

[0101]

[Table 1]

A1-1 is a case without Al ₂ O ₃ , that is, a conventional example, and Examples A1-3 to A1-9 of the present invention are A1-1.
It can be seen that the MR ratio has increased compared to This is considered to be due to the mirror reflection effect at the interface S1. However,
The Al ₂ O ₃ layer is not very thin, the effect as A1-2. 0.4 nm or more is required. Conversely, if the Al ₂ O ₃ layer is too thick, the MR ratio will decrease. This is considered to be because if the thickness of Al ₂ O ₃ is too large, the surface properties deteriorate, and the specular reflection effect is rather reduced. From this viewpoint, the thickness of the Al ₂ O ₃ layer is 2
The thickness is preferably 0 nm or less, more preferably 2 nm or less.

Next, the second ferromagnetic layer 5 and the antiferromagnetic layer 7
In order to enhance the mirror reflection effect of electrons in the above, an MR element having the following configuration using an α-Fe ₂ O ₃ film as the antiferromagnetic material 7 was manufactured. Table 1 shows the measurement results of this sample in the same manner as in A1.

A2: Ta (5) / Al ₂ O ₃ (1) / Ni
_0.80 Fe _0.20 (5) / Co (1) / Cu (2.2) / C
o (2) / α-Fe ₂ O ₃ (30) As shown in Table 1, when an α-Fe ₂ O ₃ film is used as an antiferromagnetic material, when a Pt—Mn film is used in the same configuration, A1
The MR ratio is significantly increased as compared with −4. However, Hp decreases, and the stability as a magnetoresistive element decreases.

[0105] In addition, α-Fe ₂ O ₃ in order to investigate the composition of the film, direct α-Fe ₂ O ₃ film about 100 on the Si substrate
When formed with a thickness of nm and analyzed by EPMA, it was found that Fe / O = 1 / 1.42.

When the manufacturing conditions such as the sputtering pressure were changed, the composition slightly changed. However, when Fe / O was in the range of 1 / 1.35 to 1 / 1.6, there was an effect of increasing the MR ratio. Was. Therefore, the present invention is effective in this composition range.

Next, using the films of the present invention A1-3 to A1-9 and Comparative Examples A1-1 and A2 as the MR element 109,
The MR head as shown in FIG. 3 was constructed, and the characteristics were evaluated. In this case, using the Al ₂ O ₃ -TiC substrate as the substrate, the material of the shield 10 and 15 using a Ni _0.8 Fe _0.2 alloy, the shield gap 11 and 14 with Al ₂ O _3.

The hard bias section 12 has Co-Pt
The lead portion 13 was made of Au using an alloy. Also, the pinned layer (the second ferromagnetic layer 3) is set such that the direction of the easy axis of magnetization is perpendicular to the direction of the signal magnetic field to be detected.
The magnetic film was anisotropic so that the direction of the easy axis of the ferromagnetic layer 5) was parallel to the direction of the signal magnetic field to be detected.
In this method, when a magnetic film is formed, a magnetic field is applied by a permanent magnet in a direction in which anisotropy is to be provided in the film surface, and the heat treatment is performed while applying a magnetic field.

[0109] About 4 kA / m (50O
Table 1 shows the results of evaluating the output of both heads by applying the AC signal magnetic field of e). In this case, the output of A1-1 is shown as a relative value with 1 being set. The embodiment of the present invention has a higher output than the conventional example A1-1.

Example 2 An MR element 100B having the structure shown in FIG. 1B was manufactured in the same manner as in Example 1. In this case, a Si substrate is used as the substrate 1 and P is used as the antiferromagnetic material.
A t-Mn or NiO film was used. The configuration is shown below.

B1: Ta (5) / Pt _0.4 Mn _0.6 (1
5) / Co _0.90 Fe _0.10 (2) / Cu (2) / Co _0.90
Fe _0.10 (1) / Ni _0.8 Fe _0.20 (6) / Al ₂ O
₃ (2) / Ta (5) B2: Ta (5) / Pt _0.4 Mn _0.6 (15) / Co _0.9
0Fe _0.10 (2) / Cu (2) / Co _0.90 Fe
_0.10 (1) / Ni _0.8 Fe _0.20 (6) / Ta (5) B3: Ta (5) / NiO (15) / Co _0.90 Fe _0.10
(2) / Cu (2) / Co _0.90 Fe _0.10 (1) / Ni
_0.8 Fe _0.20 (6) / Al ₂ O ₃ (2) / Ta (5) After heat treatment in the same manner as in Example 1, evaluation was performed in the same manner as in Example 1, and the following results were obtained. However, only B3 was evaluated without heat treatment.

[0112]

[Table 2]

The embodiment B1 of the present invention is different from the comparative example B2.
And the first ferromagnetic layer 3 (Co_0.90Fe _0.10(1) / Ni
_0.8Fe_0.20(6)) and a non-magnetic high resistance layer 8 (A
l_TwoO_Three(2)) is formed before the protective layer Ta
At the interface S1 between the nonmagnetic high-resistance layer 8 and the first ferromagnetic layer 3,
The probability that electrons are specularly reflected is high, and the MR ratio is high. Ma
Further, when a NiO film is used as the antiferromagnetic material layer 7 (Example
B3) The MR ratio is higher than when the antiferromagnetic layer is made of metal.
No.

Next, in the same manner as in Example B3, FIG.
(B) An MR element having the following configuration using an indirect coupling film as the second ferromagnetic layer 5 was prepared. However, in this case, the heat treatment was performed while applying a magnetic field of 400 kA / m (5 kOe).

B4: Ta (5) / NiO (15) / Co
_0.90 Fe _0.10 (3) / Ru (0.7) / Co _0.90 Fe
_0.10 (2) / Cu (2) / Co _0.90 Fe _0.10 (1) / N
i _0.8 Fe _0.20 (6) / Al ₂ O ₃ (2) / Ta (5) The magnetoresistance change of the MR element was evaluated in the same manner as in Example 1. Table 2 shows the results. As shown in Table 2, Example B4 of the present invention has a larger bias magnetic field Hp although the MR ratio is lower than B3 in which no indirect exchange coupling film is used, and the magnetic field direction of the pinned layer is smaller. It is more stable and stable operation as an MR element can be expected.

In the above, the case where the Co—Fe alloy is used as the magnetic layer used for the indirect exchange coupling film has been described. However, Co and Co—Ni—Fe alloy can be used instead of Co. The thickness of the magnetic layer at this time is 1n
It is preferable that the thickness be from m to 4 nm. Also, the thicknesses of the two magnetic layers are preferably different by at least 0.5 nm or more as shown in the example.

This is because the role of the indirect coupling film is not merely to increase the bias magnetic field, but to various magnetic fields applied to the free layer, that is, the bias magnetic field from the pinned layer.
This is because it also has a role of canceling a magnetic field or the like due to the measurement current. As the nonmagnetic layer used for the indirect exchange coupling film, B
In No. 4, Ru was used, but Ir can also be used. The thickness of the non-magnetic layer is preferably 0.3 nm or more and 1.2 nm or less.

Example 3 An example C1 of an MR element 200A of the type shown in FIG. 2A was manufactured in the same manner as in Example 1. At this time, a Si (100) substrate was used as the substrate, an α-Fe ₂ O ₃ film was used as the high resistance layer 8a, and an Au film was used as the metal reflection film layer 9. For comparison, the films C2 and C3 without using the high-resistance layer 8a or the metal reflective film layer 9 were produced in exactly the same manner as in Example C1 except for the above. The configuration is shown below.

C1: Ta (3) / α-Fe ₂ O ₃ (1.
5) / Au (1) / Ni _0.68 Fe _0.20 Co _0.12 (5) /
Co (1) / Cu (2.5) / Co (3) / Ir _0.2 M
n _0.8 (8) / Ta (3) C2: Ta (3) / α-Fe ₂ O ₃ (1.5) / Ni _0.68
Fe _0.20 Co _0.12 (5) / Co (1) / Cu (2.5)
/ Co (3) / Ir _0.2 Mn _0.8 (8) / Ta (3) C3: Ta (3) / Au (1) / Ni _0.68 Fe _0.20 Co
_0.12 (5) / Co (1) / Cu (2.5) / Co (3)
/ Ir _0.2 Mn _0.8 (8) / Ta (3) After producing this film, the MR ratio was measured at room temperature in the same manner as in Example 1. Table 3 shows the results.

[0120]

[Table 3]

As is clear from Table 3, Example C of the present invention
No. 1 has a higher MR ratio than the conventional example C3. This is shown in FIG.
When the metal reflection film layer 9 is used in the configuration of FIG.
This means that it is important to appropriately select (including the high resistance layer 8a). In the case of C2, although not shown in Table 3, the free layer 3 and the metal reflection layer 9 are magnetically coupled, and the soft magnetic characteristics of the free layer are lost. It is greatly reduced and is not suitable for practical use. C1 has a higher MR ratio than C2 because the metal reflection film A
It is considered that the specular reflectance is increased by the effect of the u layer.

Next, in the same manner as in Example C1, FIG.
(A) An MR element having the following configuration using an indirect coupling film as the second ferromagnetic layer 5 was prepared.

C4: Ta (3) / α-Fe ₂ O ₃ (1.
5) / Au (1) / Ni _0.68 Fe _0.20 Co _0.12 (5) /
Co (1) / Cu (2.5) / Co (2) / Ru (0.
8) / Co (3) / Ir _0.2 Mn _0.8 (8) / Ta (3) The magnetoresistance change of the MR element was evaluated in the same manner as in Example C1. Table 2 shows the results. As shown in Table 2, Example C4 of the present invention has a larger bias magnetic field Hp although the MR ratio is lower than that of C1 not using the indirect exchange coupling film, and the magnetic field direction of the pinned layer is smaller. It is more stable and stable operation as an MR element can be expected.

In the above, the case where Co is used as the magnetic layer used for the indirect exchange coupling film has been described.
An Fe alloy or a Co—Ni—Fe alloy can also be used instead of Co. The thickness of the magnetic layer at this time is 1n
It is preferable that the thickness be from m to 4 nm. Also, the thicknesses of the two magnetic layers are preferably different by at least 0.5 nm or more as shown in the example.

This is because the role of the indirect coupling film is not merely to increase the bias magnetic field, but to various magnetic fields applied to the free layer, that is, the bias magnetic field from the pinned layer.
This is because it also has a role of canceling a magnetic field or the like due to the measurement current. As the nonmagnetic layer used for the indirect exchange coupling film, C
In No. 4, Ru was used, but Ir can also be used. The thickness of the non-magnetic layer is preferably 0.3 nm or more and 1.2 nm or less.

Example 4 An MR element 200B of the type shown in FIG. 2B was manufactured in the same manner as in Example 1.
At this time, a glass substrate is used as the substrate and the high resistance layer 8a is used.
, An Ag film was used as the metal reflection film 9. As a comparative example, a D2-D4 film without the high resistance layer 8a and the metal reflection film 9 was produced.

D1: NiO (50) / Co _0.5 Fe
_0.5 (2) / Cu (3) / Co _0.9 Fe _0.1 (2) / Ag
(0.8) / AlN (1) / Ta (5) D2: NiO (50) / Co _0.5 Fe _0.5 (2) / Cu
(3) / Co _0.9 Fe _0.1 (2) / AlN (1) / Ta
(5) D3: NiO (50) / Co _0.5 Fe _0.5 (2) / Cu
(3) / Co _0.9 Fe _0.1 (2) / Au (0.8) / Ta
(5) D4: NiO (50) / Co _0.5 Fe _0.5 (2) / Cu
(3) / Co _0.9 Fe _0.1 (2) / Ta (5) D5: NiO (50) / Co _0.5 Fe _0.5 (2) / Cu
(3) / Co _0.9 Fe _0.1 (2) / Cu (0.8) / Ag
(0.8) / AlN (1) / Ta (5) After forming these films, MR was performed at room temperature in the same manner as in Example 1.
The ratio was measured. Table 4 shows the results.

[0128]

[Table 4]

As is clear from Table 4, Example D of the present invention
As for No. 1, it is clear that the MR ratio is much higher than those of Comparative Examples D3 and D4. D2 is one embodiment of the present invention, but D1 using the metal reflection film 9 has a higher MR ratio. This is considered to be because D1 more effectively mirror-reflects electrons at the interface S2 of the high-resistance layer 8a.

In Example D5, the Cu (1) layer has the effect of improving the soft magnetic characteristics of the free layer and further amplifying the effect of the specular reflection film.

In the above, the case where a NiO film is used as the antiferromagnetic material 7 and AlN is used as the high resistance layer 8a has been described. However, as the antiferromagnetic material 7, Al ₂ O ₃ and high resistance layer 8a are used. Even if Al ₂ O ₃ is used, an excellent magnetoresistance effect element can be formed. As an example, D6: α-Fe ₂ O ₃ (50) / Co _0.5 Fe _0.5 (2) /
Cu (3) / Co _0.9 Fe _0.1 (2) / Cu (0.8) /
Ag (0.8) / Al ₂ O ₃ (1) / Ta (5) was prepared and evaluated in the same manner as D5. As shown in Table 4, a large MR ratio was exhibited.

Example 5 First, a surface treatment was performed on an Si substrate using an ion beam under various conditions to change the surface roughness. In the same manner as in Example 1, an MR of the type shown in FIG.
Element 200A was produced. In this case, Al ₂ O ₃ was used as the high resistance layer 8a, Ag was used as the metal reflection film layer 9, and Ir _0.2 Mn _0.8 film was used as the antiferromagnetic material 7. E1: Ta (3) / Al ₂ O ₃ (1) / Ag (1) / Ni
_0.8 Fe _0.2 (3) / Co (1) / Cu (2) / Co
(2) / Ir _0.2 Mn _0.8 (10) Table 5 shows the surface roughness and MR ratio of the prepared sample. The surface roughness in this case is determined by STM (Scanning Tunn).
eling microscopy). 10nm randomly on the surface of a 10mm square sample
Ten areas of × 10 nm were selected, the difference between the highest point and the lowest point in each area was defined as the surface roughness of the area, and the average of the differences at ten points was defined as the surface roughness of the sample.

[0133]

[Table 5]

From the results shown in Table 5, it is understood that those having a surface roughness of 0.5 nm or less show a large MR ratio. The surface roughness is related to the roughness of the layer interface. If the surface roughness is rough, the layer interface where electrons are scattered is also considered to be rough, so the specular reflectivity of the electrons decreases and the MR ratio decreases. It is thought to be.

[0135]

As described above, the present invention utilizes the specular reflection effect of electrons by using a thin high resistance layer, so that the magnetoresistive effect element and the magnetoresistive effect type exhibiting a large MR ratio. A head and a hard disk device using the same can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a cross section of a magnetoresistive element of the present invention.

FIG. 2 is a schematic view of a cross section of another magnetoresistive element according to the present invention.

FIG. 3 is a sectional view of an MR head according to the present invention.

FIG. 4 is a three-dimensional view of the MR head of the present invention.

FIG. 5 is a cross-sectional view of an MR head and a magnetic disk of the present invention.

FIG. 6 is a cross-sectional view of a recording head-integrated MR head of the present invention.

FIG. 7 is a sectional view of another MR head of the present invention.

FIG. 8 shows an example of a magnetoresistance curve of the magnetoresistance effect element of the present invention.

FIG. 9 is a side view of the hard disk drive of the present invention.

FIG. 10 is a plan view of the hard disk device of the present invention.

FIG. 11 is a schematic view of a cross section of another conventional magnetoresistance effect element.

FIG. 12 is a schematic view of a cross section of another conventional magnetoresistance effect element.

FIG. 13 is a schematic view of a cross section of a conventional magnetoresistance effect element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Underlayer 3 First ferromagnetic layer (free layer) 4 Nonmagnetic layer 5 Second ferromagnetic layer 7 Antiferromagnetic layer 8 Nonmagnetic high resistance layer 8a High resistance layer 9 Metal reflection film layer 10 Shield DESCRIPTION OF SYMBOLS 11 Shield gap 12 Hard bias part 13 Lead part 14 Shield gap 15 Upper shield 16 Upper recording core 40 Recording gap part 109 MR element part

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mitsuo Satomi 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Terms (reference) 5D034 BA03 BA15 BA16 BA17 BA18 BB01

Claims (35)

[Claims] A first non-magnetic high-resistance layer, a first ferromagnetic layer,
A magnetoresistive element having a configuration in which a nonmagnetic layer, a second ferromagnetic layer, and an antiferromagnetic layer are sequentially laminated. 2. The magnetoresistive element according to claim 1, wherein the non-magnetic high-resistance layer has a property of easily reflecting conduction electrons while maintaining the direction of electron spin. 3. The non-magnetic high-resistance layer has a thickness of 0.4 n.
The magnetoresistive element according to claim 1, which has a length of not less than m and not more than 20 nm. 4. The non-magnetic high-resistance layer has a thickness of 0.4 n.
The magnetoresistance effect element according to claim 3, wherein the diameter is not less than m and not more than 2 nm. 5. The magnetoresistance effect element according to claim 1, wherein said nonmagnetic high resistance layer contains an oxide of Al. 6. The non-magnetic high-resistance layer has a reflective surface in contact with the first ferromagnetic layer, and at least a portion of the reflective surface is smooth when viewed on a Angstrom level. 3. The magnetoresistive effect element according to item 1. 7. The magnetoresistive element according to claim 6, wherein at least 10% or more of the reflection surface is a smooth surface having irregularities of 0.5 nm or less. 8. The magnetoresistive element according to claim 1, wherein the antiferromagnetic layer contains an oxide. 9. The magnetoresistive element according to claim 8, wherein said oxide contains α-Fe ₂ O ₃ . 10. The magnetoresistive element according to claim 8, wherein said oxide contains NiO. 11. The non-magnetic layer contains Cu, and at least one of the first ferromagnetic layer and the second ferromagnetic layer has at least one of Fe, Ni, Co, and an alloy thereof. The magnetoresistive element according to claim 1, comprising: 12. The second ferromagnetic layer includes a second nonmagnetic layer, and a third ferromagnetic layer and a fourth ferromagnetic layer that are stacked with the second nonmagnetic layer interposed therebetween. The magnetoresistance effect element according to claim 1, further comprising: 13. At least one of the third ferromagnetic layer and the fourth ferromagnetic layer contains at least one of Co and a Co—Fe alloy, and the second nonmagnetic layer contains Ru and 13. The magnetoresistive element according to claim 12, comprising at least one of Ir. 14. A magnetoresistive element having a structure in which a high resistance layer, a metal reflection layer, a first ferromagnetic layer, a first nonmagnetic layer, a second ferromagnetic layer, and an antiferromagnetic layer are sequentially stacked. Effect element. 15. The high-resistance layer has a property of easily reflecting conduction electrons while maintaining the spin direction of electrons.
The magnetoresistance effect element according to claim 14. 16. The magnetoresistive element according to claim 14, wherein said metal reflection film layer contains at least one of Au and Ag as a main component. 17. The magnetoresistive element according to claim 14, wherein the thickness of the high resistance layer is 0.4 nm or more and 20 nm or less. 18. The magnetoresistive element according to claim 17, wherein the thickness of the high resistance layer is 0.4 nm or more and 2 nm or less. 19. The magnetoresistive element according to claim 14, wherein said high-resistance layer contains an oxide of Al. 20. The magnet of claim 14, wherein the high resistance layer has a reflective surface in contact with the metal reflective film layer, and at least a portion of the reflective surface is smooth when viewed on a Angstrom level. Resistance effect element. 21. The magnetoresistive element according to claim 20, wherein at least 10% or more of the reflection surface is a smooth surface having irregularities of 0.5 nm or less. 22. The magnetoresistive element according to claim 14, wherein the high resistance layer contains α-Fe ₂ O ₃ . 23. The antiferromagnetic layer contains an oxide.
The magnetoresistance effect element according to claim 14. 24. The oxide comprises α-Fe ₂ O ₃ ,
A magnetoresistive element according to claim 23. 25. The magnetoresistive element according to claim 23, wherein the oxide contains NiO. 26. The first nonmagnetic layer contains Cu, and at least one of the first ferromagnetic layer and the second ferromagnetic layer is made of one of Fe, Ni, Co, and an alloy thereof. The magnetoresistive element according to claim 14, comprising at least one of the following. 27. The second ferromagnetic layer includes a second nonmagnetic layer, and a third ferromagnetic layer and a fourth ferromagnetic layer that are stacked via the second nonmagnetic layer. The magnetoresistance effect element according to claim 14, further comprising: 28. At least one of the third ferromagnetic layer and the fourth ferromagnetic layer contains at least one of Co and a Co—Fe alloy, and the second nonmagnetic layer contains Ru and 28. The magnetoresistive element according to claim 27, comprising at least one of Ir. 29. The magnetoresistive element according to claim 14, wherein a second nonmagnetic layer is further laminated between the metal reflection film layer and the first ferromagnetic layer. 30. A magnetoresistive element having a structure in which a nonmagnetic high resistance layer, a first ferromagnetic layer, a first nonmagnetic layer, a second ferromagnetic layer, and an antiferromagnetic layer are sequentially stacked. A magnetoresistive head comprising: a bias application unit that controls a magnetic domain of the first ferromagnetic material; and a recording unit. 31. The second ferromagnetic layer includes a second nonmagnetic layer, and a third ferromagnetic layer and a fourth ferromagnetic layer stacked with the second nonmagnetic layer interposed therebetween. 31. The magnetoresistive head according to claim 30, further comprising: 32. A magnetoresistive element having a structure in which a high resistance layer, a metal reflection layer, a first ferromagnetic layer, a first nonmagnetic layer, a second ferromagnetic layer, and an antiferromagnetic layer are sequentially stacked. A magnetoresistive head comprising: an effect element; a bias applying unit that controls a magnetic domain of the first ferromagnetic material; and a recording unit. 33. The magnetoresistive head according to claim 32, wherein a second nonmagnetic layer is further laminated between the metal reflection film layer and the first ferromagnetic layer. 34. A hard disk drive for recording and reproducing information on and from a disk by using a magnetoresistive head, wherein the hard disk device includes the magnetoresistive head and a slider for holding the magnetoresistive head. A magnetoresistive head support mechanism; and driving means for tracking the magnetoresistive head via the magnetoresistive head support mechanism. The magnetoresistive head includes a nonmagnetic high-resistance layer, A magnetoresistive element having a configuration in which one ferromagnetic layer, a first nonmagnetic layer, a second ferromagnetic layer, and an antiferromagnetic layer are sequentially stacked; and controlling the magnetic domain of the first ferromagnetic substance A hard disk device including a bias applying unit and a recording unit. 35. A hard disk drive for recording and reproducing information on a disk by using a magnetoresistive head, wherein the hard disk device includes the magnetoresistive head and a slider for holding the magnetoresistive head. A magnetoresistive head support mechanism; and a driving unit that tracks the magnetoresistive head via the magnetoresistive head support mechanism. The magnetoresistive head includes a high-resistance layer and a metal reflective film. A magnetoresistive effect element having a structure in which a layer, a first ferromagnetic layer, a first nonmagnetic layer, a second ferromagnetic layer, and an antiferromagnetic layer are sequentially stacked; A hard disk drive including a bias applying unit for controlling a magnetic domain and a recording unit.