JPH11328624A - Magneto-resistance effect device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a magnetization direction of a free layer by setting a magnetic filed generated by a sensing current in an unbalance condition without deteriorating magneto-resistance effect in a magneto-resistance effect device. SOLUTION: A dual spin valve type magneto-resistance effect device has first, second and third ferromagnetic layers 2, 4, 6 separated from each other by first and second non-magnetic metal layers 3, 5. The magnetization directions of the first and third ferromagnetic layers 2, 6 are fixed in parallel to each other. The first non-magnetic metal layer 3 is made of a layer including Pd and having a relatively large specific resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive effect element, and more particularly to a non-magnetic metal layer for reducing the effect of a magnetic field due to magnetostatic coupling without deteriorating the magnetoresistance effect, that is, the structure of an intermediate layer. The present invention relates to a magnetoresistive element utilizing the dual spin valve effect.

[0002]

2. Description of the Related Art With the growing demand for miniaturization and large-capacity hard disk devices in recent years, research and development of hard disk devices capable of high-density magnetic recording have been rapidly advanced. As a read head, a magnetic sensor using a giant magnetoresistance (GMR) effect capable of obtaining a large output in a low magnetic field has been developed.

For example, IBM has proposed a "magnetoresistive sensor utilizing the spin valve effect (see Japanese Patent Application Laid-Open No. 4-358310). This magnetic sensor comprises two magnetic layers separated by a non-magnetic metal layer. It has a non-coupled ferromagnetic layer, and an antiferromagnetic layer typified by FeMn is attached to one of the ferromagnetic layers to form a sandwich structure in which the magnetization M of the ferromagnetic layer is fixed. .

In this magnetic sensor, when an external magnetic field is applied, the other ferromagnetic layer whose magnetization is not fixed,
That is, since the magnetization direction of the free layer is freely rotated in accordance with the external magnetic field, an angle difference is generated between the magnetization direction of the ferromagnetic layer having a fixed magnetization, that is, the pinned layer. Become.

Since the scattering depending on the spin of the conduction electrons changes depending on the angle difference and the electric resistance changes, the change in the electric resistance is changed by flowing a constant sense current. As a result, the state of the external magnetic field, that is, the signal magnetic field from the magnetic recording medium is obtained, and the magnetoresistance change rate of the spin valve magnetoresistance sensor is about 5%.

In order to increase the efficiency of such a spin valve magnetoresistive sensor, IBM has also proposed a "double spin sensor".
A valve magnetoresistive sensor (see Japanese Patent Application Laid-Open No. 6-223336) has been proposed. This dual spin valve magnetoresistive element has a spin valve structure symmetrically stacked around a free layer. Since a magnetoresistance change of about twice is obtained by this configuration, such a dual spin valve magnetoresistance effect element will be described with reference to FIG.

FIG. 4 is a perspective view showing the antiferromagnetic layer 31 to the antiferromagnetic layer 37 separated from each other. First, a substrate (not shown)
A Ta layer and a NiFe layer are sequentially laminated while applying a first magnetic field in a predetermined direction by a sputtering method to form a base layer (not shown). Then, the antiferromagnetic layer 31 is formed. A pinned layer 32 made of a magnetic material layer, a Cu intermediate layer 33 made of nonmagnetic metal Cu, a free layer 34 made of a ferromagnetic material layer, a Cu intermediate layer 35, a pinned layer 36 made of a ferromagnetic material layer, After sequentially stacking the ferromagnetic layers 37, heat treatment is performed in a vacuum with a second magnetic field orthogonal to the first magnetic field being applied to determine the magnetization directions of the antiferromagnetic layers 31, 37. Thereby, the basic structure of the magnetoresistive effect element is formed.

As shown in the figure, the magnetization directions M ₃ and M ₄ of the pinned layers 32 and 36 are fixed to the magnetization directions M ₁ and M ₂ of the antiferromagnetic layers 31 and 37, while the magnetization directions of the free layer 34 are fixed. direction M ₅ is the magnetic field 38 due to static magnetic coupling of the upper and lower pinned layers 32 and 36, in the plane indicated by the thin solid line in FIG. 4, in the direction of the arrow in the direction of the arrow shown by a broken line shown by the solid line, i.e., pinned The layers 32 and 36 rotate in directions antiparallel to the magnetization directions M ₃ and M ₄ .

[0009] the rotation of the magnetization direction M ₅ of such free layer 34, the operation center point in the absence of an externally applied magnetic field, i.e., from zero magnetic field strength that gives the center value of the maximum resistance and the minimum resistance is the center This causes a problem that the bias point of the magnetoresistive sensor fluctuates with the fluctuation of the operation center point, and a sufficient dynamic range cannot be secured.

The magnetization direction M of the free layer 34
The rotation of ₅ is performed by a heat treatment in a magnetic field typified by a resist hardening process during the process of incorporating the dual spin-valve magnetoresistive element as a head, or when the dual spin-valve magnetoresistive element is operated as a head. Is also caused by the leakage magnetic field generated from the shield layer sandwiching the upper and lower sides.

In a conventional spin valve magnetoresistive element having a single structure, a magnetic field 38 due to such a magnetostatic coupling is used.
Was offset by the magnetic field due to the sense current by appropriately selecting the value of the sense current 39.
In the dual spin-valve magnetoresistive element, a magnetic field 40, 41 due to the sense current is generated by a sense current 39 flowing through two low resistance Cu intermediate layers 33, 35.
However, the magnetic fields 40 and 41 generated by the sense current are equal to each other, and an induced magnetic field acts in the opposite direction on the free layer 34. As a result, a magnetic field 4 generated by the sense current is generated.
Impact of 0,41 will to be canceled, it is not possible to control the magnetization direction M ₅ of the free layer 34.

The antiferromagnetic layers 31 and 37 of such a dual spin-valve magnetoresistive element are composed of Pd.P.
When t.Mn is used, unlike the conventional FeMn, the antiferromagnetic property is not lost even if the lower layer has any crystal structure, so that either the upper or lower pinned layer 32,
A fixed magnetic field can also be applied to 36 (if necessary, see Japanese Patent Application No. 8-257068).

[0013] In order to solve the problems of rotation of the magnetization direction M ₅ of such free layer 34, the present inventors have discovered that by unbalanced magnetic fields 40, 41 by the sense current, the magnetic field due to magnetostatic coupling Since it is proposed to cancel the effect of the present invention (if necessary, refer to Japanese Patent Application No. 9-261641), this improved dual spin-valve magnetoresistive element will be described with reference to FIG. FIG. 5 is also a perspective view showing the antiferromagnetic layer 31 to the antiferromagnetic layer 37 separately from each other. First, Al ₂ O ₃ —Ti
An Nb layer and a NiFe layer are sequentially laminated on a substrate (not shown) made of C ceramic by a sputtering method to form a base layer (not shown).

Subsequently, the sputtering method is also used.
And Pd₃₁Pt₁₇Mn₅₂An antiferromagnetic layer 31 made of
Co₉₀Fe_TenA pinned layer 32, a Cu intermediate layer 33,
Co ₉₀Fe_Ten/ Ni₈₁Fe₁₉/ Co₉₀Fe_TenConsisting of 3
Free layer 34 having a layer structure, Ag intermediate layer 42, Co₉₀Fe_Ten
A pinned layer 36 made of₃₁Pt₁₇Mn₅₂From
The antiferromagnetic layers 37 are sequentially laminated.

Next, in order to fix the magnetization directions of the pinned layers 32 and 36, a heat treatment is performed at 230 ° C. for 1 to 3 hours in a vacuum while applying a DC magnetic field of 100 kA / m to thereby obtain an antiferromagnetic material. The basic structure of the magnetoresistive element is formed by setting the magnetization direction of the layers 31 and 37 to the direction of the applied DC magnetic field.

In this case, as shown in FIG.
The magnetization directions M ₃ and M ₄ of the antiferromagnetic layers 31 and 3
7 are fixed to the magnetization directions M ₁ and M ₂ , while the free layer 3
The magnetization direction M ₅ 4 can measure the external magnetic field by passing it to the direction which is substantially perpendicular to the magnetization direction M _3, M ₄ of the pinned layer 32 and 36, the sense current 39 between electrodes (I _sens) .

This is because the Cu intermediate layer 33 and the Ag intermediate layer 42
Are different from each other, the Cu intermediate layer 33 (specific resistance: 1.
More sense current 39 flows to the Ag intermediate layer 42 (specific resistance: 1.47 × 10 ⁻⁶ Ω · cm) having a lower specific resistance than that of 55 × 10 ⁻⁶ Ω · cm. The magnetic field 40 due to the sense current on the layer 42 side and the magnetic field 41 due to the sense current on the Cu intermediate layer 33 side become asymmetric, and the magnetic field 40 due to the magnetostatic coupling is reduced by the magnetic field 40 due to the sense current which becomes a relatively large induced magnetic field. This is because they are offset.
The specific resistance is a specific resistance at 0 ° C., and the same applies hereinafter.

In the above-mentioned application, both the intermediate layers are made of Cu, and the thickness of the intermediate layer on the side of the binding layer 36 is made relatively large, so that the magnetic field 38 due to the magnetostatic coupling is obtained.
And the intermediate layer on the side of the binding layer 36 is made of Cu, and the intermediate layer on the side of the pinned layer 32 is made of Pt (specific resistance 9.81 × 10 ⁻⁶ Ω · cm) having a higher specific resistance than Cu. )
It has also been proposed to cancel out the effect of the magnetic field 38 due to the magnetostatic coupling by using such a configuration.

[0019]

However, in such an improved dual spin valve magnetoresistive element,
Where non-magnetic metals other than Cu as the intermediate layer, the magnetoresistance effect obtained it is known that becomes smaller as compared with the case of using Cu, magnetization direction M ₅ of the free layer 34 can be controlled However, there is a problem that the output obtained as an element is reduced.

Therefore, an object of the present invention is to control the magnetization direction of the free layer by unbalancing the magnetic field generated by the sense current without impairing the magnetoresistance effect.

[0021]

FIG. 1 is an explanatory view of the principle configuration of the present invention. Referring to FIG. 1, means for solving the problems in the present invention will be described. See FIG. 1. (1) The present invention provides a first ferromagnetic layer 2 and a second ferromagnetic layer 4 separated from each other by a first non-magnetic metal layer 3 and a second non-magnetic metal layer 5, respectively. And a third ferromagnetic layer 6, wherein the second ferromagnetic layer 4 is disposed between the first nonmagnetic metal layer 3 and the second nonmagnetic metal layer 5, and The magnetization directions of the first ferromagnetic layer 2 and the third ferromagnetic layer 6 are fixed to be parallel to each other, and the specific resistances of the first nonmagnetic metal layer 3 and the second nonmagnetic metal layer 5 are mutually different. In different dual spin valve type magnetoresistive elements,
The first nonmagnetic metal layer 3 having a relatively large specific resistance contains at least Pd.

As described above, when the sense current flowing on the first non-magnetic metal layer 3 side and the sense current flowing on the second non-magnetic metal layer 5 side are made asymmetric, the magnetic field due to the sense current is made asymmetric. The first non-magnetic metal layer 3 having a relatively large specific resistance is formed of at least Pd (specific resistance: 10.0 ×
10 ⁻⁶ Ω · cm) can prevent the reduction of the magnetoresistance effect, and
The magnetization direction of the second ferromagnetic layer 4, that is, the free layer, can be arbitrarily controlled without impairing the magnetoresistance effect.

(2) The present invention is characterized in that, in the above (1), the first nonmagnetic metal layer 3 is constituted by a single layer of Pd.

As described above, the first nonmagnetic metal layer 3 having a relatively large specific resistance is desirably constituted by a single Pd layer. A resistance effect can be obtained.

(3) Further, according to the present invention, in the above (1), the first nonmagnetic metal layer 3 is formed by adding Pd, Ag, Cu, A
It is characterized by comprising a laminated structure with any one of u and Pt.

As described above, the first nonmagnetic metal layer 3 having a relatively large specific resistance has a laminated structure of Pd and any one of Ag, Cu, Au, and Pt, for example, Cu / Pd
/ Cu layered structure may be employed, whereby a magnetoresistance effect equal to or higher than that of the case of using Cu can be obtained.

(4) Further, according to the present invention, in the above (1), the first non-magnetic metal layer 3 is formed by adding Pd, Ag, Cu, A
It is characterized by comprising an alloy layer with any one of u and Pt.

As described above, the first nonmagnetic metal layer 3 having a relatively large specific resistance is an alloy layer of Pd and any one of Ag, Cu, Au and Pt, for example, Pd- It may be constituted by a Cu alloy layer, and the same magnetoresistive effect as that obtained when Cu is used can be obtained.

(5) The present invention also provides a first ferromagnetic layer 2 and a second ferromagnetic layer separated from each other by a first non-magnetic metal layer 3 and a second non-magnetic metal layer 5, respectively. A second ferromagnetic layer disposed between the first non-magnetic metal layer and the second non-magnetic metal layer; The magnetization directions of the first ferromagnetic layer 2 and the third ferromagnetic layer 6 are fixed parallel to each other, and
In a dual spin-valve magnetoresistive element in which the first nonmagnetic metal layer 3 and the second nonmagnetic metal layer 5 have different specific resistances, the first nonmagnetic metal layer 3 having a relatively large specific resistance is used. , Ta, or W in a sandwich structure sandwiched between Cu or Pd.

As described above, the first nonmagnetic metal layer 3 having a relatively large specific resistance is made of Ta having a high specific resistance (specific resistance: 12.3).
× 10 ⁻⁶ Ω · cm) or W (specific resistance: 4.9 × 10 ⁻⁶⁾
Ω · cm) may be constituted by a sandwich structure sandwiched between Cu or Pd, for example, a Cu / Ta / Cu laminated structure. Since a Cu layer or a Pd layer exists at an interface in contact with the ferromagnetic layer, the magnetoresistance is reduced. The effect is not lost.

(6) The present invention also provides a first ferromagnetic layer 2 and a second ferromagnetic layer separated from each other by a first nonmagnetic metal layer 3 and a second nonmagnetic metal layer 5, respectively. A second ferromagnetic layer disposed between the first non-magnetic metal layer and the second non-magnetic metal layer; The magnetization directions of the first ferromagnetic layer 2 and the third ferromagnetic layer 6 are fixed parallel to each other, and
In a dual spin-valve magnetoresistive element in which the first nonmagnetic metal layer 3 and the second nonmagnetic metal layer 5 have different specific resistances, the first nonmagnetic metal layer 3 having a relatively large specific resistance is used. , Ta or W, and at least one of Cu and Pd.

As described above, the first nonmagnetic metal layer 3 having a relatively large specific resistance is an alloy layer of at least one of Ta or W having high specific resistance and at least one of Cu or Pd, for example, Ta. -Cu alloy layer, the first
Cu or Pd is contained in the nonmagnetic metal layer 3 of
Deterioration of the magnetoresistance effect is reduced.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetoresistive element according to a first embodiment of the present invention will now be described with reference to FIG. FIG. 2 is a sectional view of a main part of a laminated body for forming a dual spin-valve magnetoresistive element.
30 Oe (≒) on a silicon substrate 11 having a (0) plane as a main surface.
While applying a magnetic field of 2.4 kA / m), a 5 nm thick Nb layer and a 5 nm thick NiF
The underlayer 12 is formed by sequentially stacking the e layers.

Subsequently, while applying a magnetic field of 30 Oe, a thickness of 10 to 25 n
m, for example, an antiferromagnetic layer 13 made of Pd ₃₂ Pt ₁₇ Mn _{51 having} a thickness of 25 nm, and a C layer having a thickness of 1 to 4 nm, for example, 2 nm.
pinned layer 14 consisting o ₉₀ Fe _10, the thickness of 2.0 to 8.0
Pd intermediate layer 15 having a thickness of 2 nm, for example, 2.5 nm.
m of Co ₉₀ Fe ₁₀ / thickness 4nm Ni ₈₁ Fe ₁₉ / thickness 2
Free layer 16 having a three-layer structure of nmCo ₉₀ Fe ₁₀ , Cu intermediate layer 17 having a thickness of 2.0 to 8.0 nm, for example, 2.5 nm, and Co ₉₀ Fe having a thickness of 1 to 4 nm, for example, 2 nm
_A pinned layer 18 of ₁₀ and a thickness of 10 to 25 nm,
For example, an antiferromagnetic layer 19 of Pd ₃₂ Pt ₁₇ Mn _{51 of} 25 nm is sequentially laminated.

Next, in order to fix the magnetization directions of the pinned layers 14 and 18, a direction perpendicular to the magnetic field applied at the time of film formation is set 20.
While applying a magnetic field of 00 Oe (≒ 160 kA / m),
The basic structure of the magnetoresistive element is formed by performing a heat treatment at 230 ° C. for 1 hour in a vacuum to change the magnetization direction of the antiferromagnetic layers 13 and 19 to the direction of the applied magnetic field.

In this case as well, in the heat treatment step at 230 ° C., the free layer is formed so that the interdiffusion between Pd and Cu constituting the Pd intermediate layer 15 and the Cu intermediate layer 17 and Ni ₈₁ Fe ₁₉ does not occur. 16 with Co ₉₀ Fe ₁₀ as a barrier
To form a three-layer structure.

Next, although not shown, this laminated structure is patterned into a stripe shape having a length of 100 μm and a width of 1 μm so that the longitudinal direction of the element is perpendicular to the fixed magnetization direction of the pinned layers 14 and 18. After that, by forming a four-terminal electrode pattern made of a Cu pattern having a thickness of 200 nm so that the element width becomes 5 μm,
A dual spin valve magnetoresistive element is completed.

In this case, Pd constituting the Pd intermediate layer 15
(Resistivity: 10.0 × 10 ⁻⁶ Ω · cm) is Cu
Cu (specific resistance: 1.55 × 10 ⁻⁶⁾ constituting the intermediate layer 17
Ω · cm) or more, the magnetic field can be generated by a large sense current even if a symmetrical structure having the same thickness is formed. offsetting the magnetization directions M ₅ of the free layer 16 may be a direction that is substantially perpendicular to the magnetization direction M _3, M ₄ of the pinned layers 14 and 18, the outside by passing a sense current I _sens between electrodes The applied magnetic field can be accurately measured.

According to the simulation, Pd is C
It has been reported that a magnetoresistance effect equal to or higher than that of u can be obtained (see, for example, Kai and Shiiki, 21st Annual Meeting of the Japan Society of Applied Magnetics, 4pc-5, 1997).
By using the Pd intermediate layer 15, a high resistance intermediate layer can be formed without impairing the magnetoresistance effect and without breaking the symmetry of the layer thickness.

In place of the Pd intermediate layer 15, Cu / P
d or Pd such as Cu / Pd / Cu and Cu, Ag (resistivity: 1.47 × 10 ⁻⁶ Ω · cm), Au (resistivity:
2.05 × 10 ⁻⁶ Ω · cm), Pt (specific resistance: 9.81)
(× 10 ⁻⁶ Ω · cm), the intermediate layer may be composed of a laminated structure with any metal, and the presence of Pd does not impair the magnetoresistive effect, and the layer thickness is symmetric. A high resistance intermediate layer can be formed without losing the properties.

In place of the Pd intermediate layer 15, Pd-C
The intermediate layer may be composed of an alloy layer of Pd such as u and any of the metals Cu, Ag, Au and Pt. Can be constituted.

Next, a second embodiment of the present invention will be described with reference to FIG. 3, except that the structure of the intermediate layer on the pinned layer 14 side is the same as that of the first embodiment. Note that FIG.
FIG. 3A is a cross-sectional view of a main part of a laminated body for forming a dual spin-valve magnetoresistive element.
(B) is an enlarged view of a multilayer intermediate layer. First, while applying a magnetic field of 30 Oe (≒ 2.4 kA / m) to the silicon substrate 11 having the (100) plane as a main surface, as shown in FIG.
An Nb layer having a thickness of 5 nm and a NiFe layer having a thickness of 5 nm are sequentially stacked by a sputtering method to form the underlayer 12.

Subsequently, a magnetic field of 30 Oe was applied in the same manner.
While sputtering, the thickness is 10 to 25 n
m, for example, 25 nm of Pd₃₂Pt₁₇Mn₅₁Consisting of anti
Ferromagnetic layer 13, 1-4 nm thick, for example, 2 nm C
o₉₀Fe_TenPinned layer 14, made of Cu / Ta / Cu
Multilayer intermediate layer 20 having a three-layer structure comprising ₉₀
Fe_Ten/ Ni with a thickness of 4 nm₈₁Fe₁₉/ Thickness 2nmCo₉₀
Fe_TenFree layer 16 having a three-layer structure consisting of
8.0 nm, for example, 2.5 nm Cu intermediate layer 17, thickness
1 to 4 nm, for example, 2 nm of Co₉₀Fe_TenConsists of
The pinned layer 18 and a thickness of 10 to 25 nm, for example, 2
5 nm Pd₃₂Pt₁₇Mn₅₁Antiferromagnetic layer 19 made of
Are sequentially laminated.

Referring to FIG. 3B, the multilayer intermediate layer 20 in this case has a thickness of, for example, 0.7 nm.
Cu layer 21, a 1.0 nm thick Ta layer 22, a thickness of 0.1 nm.
It has a structure in which 7 nm Cu layers 23 are sequentially laminated.

Next, in order to fix the magnetization directions of the pinned layers 14 and 18, a direction perpendicular to the magnetic field applied at the time of film formation is set to 20.
While applying a magnetic field of 00 Oe (≒ 160 kA / m),
The basic structure of the magnetoresistive element is formed by performing a heat treatment at 230 ° C. for 1 hour in a vacuum to change the magnetization direction of the antiferromagnetic layers 13 and 19 to the direction of the applied magnetic field.

Also in this case, in the heat treatment step at 230 ° C., the free layer 16 is formed so that the mutual diffusion between Cu and Ni ₈₁ Fe ₁₉ constituting the multilayer intermediate layer 20 and the Cu intermediate layer 17 does not occur. It has a three-layer structure using Co ₉₀ Fe _{10 serving} as a barrier.

Next, although not shown, the laminated structure is patterned into a stripe shape having a length of 100 μm and a width of 1 μm so that the longitudinal direction of the element is perpendicular to the fixed magnetization direction of the pinned layers 14 and 18. After that, by forming a four-terminal electrode pattern made of a Cu pattern having a thickness of 200 nm so that the element width becomes 5 μm,
A dual spin valve magnetoresistive element is completed.

Also in this case, the magnetization directions M ₃ and M ₄ of the pinned layers 14 and 18 are fixed to the magnetization directions M ₁ and M ₂ of the antiferromagnetic layers 13 and 19, while the magnetization directions M ₃ and M ₂ of the free layer 16 are fixed. Reference numeral ₅ denotes a direction substantially perpendicular to the magnetization directions M ₃ and M ₄ of the pinned layers 14 and 18, and the externally applied magnetic field is measured by flowing a sense current I _sens between the electrodes in the same manner as in the first embodiment. can do.

In the second embodiment, in order to increase the resistance of the intermediate layer on the pinned layer 14 side, a Ta (resistivity: 12.3 × 10 ⁻⁶ Ω · cm) layer 22 having a large specific resistance is used. Is sandwiched between Cu layers 21 and 23 having a large magnetoresistance effect, and the ferromagnetic layer, that is, the pinned layer 1
Since the interface between the layer 4 and the free layer 16 is in contact with the Cu layers 21 and 23, the resistance of the intermediate layer can be increased without impairing the magnetoresistance effect.

The high specific resistance material forming the multilayer intermediate layer 20 is not limited to Ta, but may be W (specific resistance: 4.
9 × 10 ⁻⁶ Ω · cm), and instead of the Cu layers 21 and 23 sandwiching such a high resistivity layer of Ta, W, etc., a magnetoresistance similar to Cu is used. Pd having an effect may be used.

The means for controlling the specific resistance of the intermediate layer is not limited to the multilayer intermediate layer structure.
An alloy layer of a high resistivity layer such as W and a nonmagnetic metal having a large magnetoresistance effect such as Cu and Pd may be used.
By containing u or Pd, a high-resistance intermediate layer with less deterioration of the magnetoresistance effect can be formed.

In each of the above embodiments, a single element structure is described. However, a large output may be obtained by stacking a plurality of such stacked structures. May be laminated via a nonmagnetic layer of Cu or the like, or the uppermost antiferromagnetic layer 19 may also be used as a part of the lowermost antiferromagnetic layer 13 in the next stage, The pinned layer 14 of the next stage is directly formed on the upper antiferromagnetic layer 19.
May be laminated.

In the description of each of the above embodiments, the specific resistance of the intermediate layer on the substrate side is relatively high, but the specific resistance of the intermediate layer on the free layer is relatively high. In this case, the direction in which the sense current flows may be reversed.

In the description of each embodiment of the present invention, a silicon substrate is used as a substrate.
A substrate such as an Al ₂ O ₃ —TiC substrate, a silicon substrate having a silicon O ₂ film formed on its surface, or a glass substrate may be used. A ferromagnetic material and an antiferromagnetic material which are generally used other than those described in the examples may be used.

[0055]

According to the present invention, the specific resistance of at least one of the intermediate layers of the dual spin valve magnetoresistive element can be adjusted by using Pd,
By adopting a sandwich structure with u or Pd, a high specific resistance can be obtained, and the influence of the magnetic field due to the magnetostatic coupling can be canceled without impairing the magnetoresistance effect. It is possible to realize a magnetoresistive effect element having high performance.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a basic configuration of the present invention.

FIG. 2 is an explanatory diagram of the first embodiment of the present invention.

FIG. 3 is an explanatory diagram of a second embodiment of the present invention.

FIG. 4 is an explanatory view of a conventional dual spin valve magnetoresistive element.

FIG. 5 is an explanatory diagram of a conventional improved dual spin valve magnetoresistive element.

[Explanation of symbols]

 Reference Signs List 1 first antiferromagnetic layer 2 first ferromagnetic layer 3 first nonmagnetic metal layer 4 second ferromagnetic layer 5 second nonmagnetic metal layer 6 third ferromagnetic layer 7 Second antiferromagnetic layer 11 Silicon substrate 12 Underlayer 13 Antiferromagnetic layer 14 Pinned layer 15 Pd intermediate layer 16 Free layer 17 Cu intermediate layer 18 Pinned layer 19 Antiferromagnetic layer 20 Multilayer intermediate layer 21 Cu layer Reference Signs List 22 Ta layer 23 Cu layer 31 Antiferromagnetic layer 32 Pinned layer 33 Cu intermediate layer 34 Free layer 35 Cu intermediate layer 36 Pinned layer 37 Antiferromagnetic layer 38 Magnetic field due to magnetostatic coupling 39 Sense current 40 Magnetic field due to sense current 41 Magnetic field by sense current 42 Ag intermediate layer

Claims (6)

[Claims] 1. A first ferromagnetic layer, a second ferromagnetic layer, and a third ferromagnetic layer separated from each other by a first nonmagnetic metal layer and a second nonmagnetic metal layer, respectively. A second ferromagnetic layer disposed between the first non-magnetic metal layer and the second non-magnetic metal layer;
The magnetization directions of the first ferromagnetic layer and the third ferromagnetic layer are fixed to be parallel to each other, and the first nonmagnetic metal layer and the second nonmagnetic metal layer have different specific resistances. A dual spin valve type magnetoresistive element, wherein the first nonmagnetic metal layer 3 having a relatively large specific resistance contains at least Pd. 2. The magnetoresistive element according to claim 1, wherein said first nonmagnetic metal layer is constituted by a single layer of Pd. 3. The method according to claim 1, wherein the first nonmagnetic metal layer comprises Pd and A
2. The magnetoresistive element according to claim 1, wherein said magnetoresistive element has a laminated structure with any one of g, Cu, Au and Pt. 4. The method according to claim 1, wherein the first nonmagnetic metal layer comprises Pd and A
2. The magnetoresistive element according to claim 1, wherein the magnetoresistive element is formed of an alloy layer with any one of g, Cu, Au, and Pt. 5. A first ferromagnetic layer, a second ferromagnetic layer, and a third ferromagnetic layer separated from each other by a first nonmagnetic metal layer and a second nonmagnetic metal layer, respectively. A second ferromagnetic layer disposed between the first non-magnetic metal layer and the second non-magnetic metal layer;
The magnetization directions of the first ferromagnetic layer and the third ferromagnetic layer are fixed to be parallel to each other, and the first nonmagnetic metal layer and the second nonmagnetic metal layer have different specific resistances. In a dual spin-valve magnetoresistive element, the first nonmagnetic metal layer having a relatively large specific resistance has a sandwich structure in which Ta or W is sandwiched between Cu or Pd. Resistance effect element. 6. A first ferromagnetic layer, a second ferromagnetic layer, and a third ferromagnetic layer separated from each other by a first nonmagnetic metal layer and a second nonmagnetic metal layer, respectively. A second ferromagnetic layer disposed between the first non-magnetic metal layer and the second non-magnetic metal layer;
The magnetization directions of the first ferromagnetic layer and the third ferromagnetic layer are fixed to be parallel to each other, and the first nonmagnetic metal layer and the second nonmagnetic metal layer have different specific resistances. In the dual spin-valve magnetoresistive element, the first nonmagnetic metal layer having a relatively large specific resistance is composed of an alloy layer of at least one of Ta or W and at least one of Cu or Pd. A magnetoresistive element comprising: