Magnetoresistance effect element, magnetic head, magnetic head assembly, magnetic storage system

• US 6,338,899 B1
• Filed: 06/14/1999
• Issued: 01/15/2002
• Est. Priority Date: 06/30/1998
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Fukuzawa, Hideaki, Yoshikawa, Masatoshi, Sahashi, Masashi, Koui, Katsuhiko, Iwasaki, Hitoshi, Kamiguchi, Yuzo, Saito, Kazuhiro, Hashimoto, Susumu, Fuke, Hiromi, Nakamura, Shin-ichi
• Primary Examiner(s): Kiliman, Leszek
• Application Number:
  US09/332,440
• Time in Patent Office: 946 Days
• Field of Search: 428/694.T, 428/694.TS, 428/694.TM, 428/692, 428/332, 428/336, 428/900, 360/113, 360/338, 360/32.R, 324/252
• US Class Current: 360/324.12
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• CPC Class Codes: G11B 2005/3996 large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices
• CPC Class Codes: G11B 5/3906 Details related to the use of magnetic thin film layers or to their effects
• CPC Class Codes: G11B 5/3932 Magnetic biasing films
• CPC Class Codes: G11B 5/66 the record carriers consisting of several layers
• CPC Class Codes: H01F 10/30 characterised by the composition of the intermediate layers , e.g. seed, buffer, template, diffusion preventing, cap layers H01F10/06 and H01F10/32 take precedence
• CPC Class Codes: H01F 10/3272 by use of anti-parallel coupled [APC] ferromagnetic layers, e.g. artificial ferrimagnets [AFI], artificial [AAF] or synthetic [SAF] anti-ferromagnets
• CPC Class Codes: H01F 10/3295 Spin-exchange coupled multilayers wherein the magnetic pinned or free layers are laminated without anti-parallel coupling within the pinned and free layers
• CPC Class Codes: H01F 41/325 applying a noble metal capping on a spin-exchange-coupled multilayer, e.g. spin filter deposition
• CPC Class Codes: Y10S 428/90 Magnetic feature
• CPC Class Codes: Y10T 428/1107 Magnetoresistive
• CPC Class Codes: Y10T 428/1121 Multilayer
• CPC Class Codes: Y10T 428/1143 with defined structural feature
• CPC Class Codes: Y10T 428/115 Magnetic layer composition
• CPC Class Codes: Y10T 428/1171 with defined laminate structural detail
• CPC Class Codes: Y10T 428/1193 with interlaminar component [e.g., adhesion layer, etc.]
• CPC Class Codes: Y10T 428/12326 with provision for limited relative movement between components
• CPC Class Codes: Y10T 428/12465 having magnetic properties, or preformed fiber orientation coordinate with shape
• CPC Class Codes: Y10T 428/12986 : Adjacent functionally defined components
• CPC Class Codes: Y10T 428/265 : 1 mil or less

Abstract

Disclosed are a high-sensitivity and high-reliability magnetoresistance effect device (MR device) in which bias point designing is easy, and also a magnetic head, a magnetic head assembly and a magnetic recording/reproducing system incorporating the MR device. In the MR device incorporating a spin valve film, the magnetization direction of the free layer is at a certain angle to the magnetization direction of a second ferromagnetic layer therein when the applied magnetic field is zero. In this, the pinned magnetic layer comprises a pair of ferromagnetic films as antiferromagnetically coupled to each other via a coupling film existing therebetween. The device is provided with a means of keeping the magnetization direction of either one of the pair of ferromagnetic films constituting the pinned magnetic layer, and with a nonmagnetic high-conductivity layer as disposed adjacent to a first ferromagnetic layer on the side opposite to the side on which the first ferromagnetic layer is contacted with a nonmagnetic spacer layer. With that constitution, the device has extremely high sensitivity, and the bias point in the device is well controlled.

Claims

1. A magnetoresistance effect element, comprising:

a nonmagnetic spacer layer;

first and second ferromagnetic layers separated by the nonmagnetic spacer layer, the first ferromagnetic layer having a magnetization direction at an angle relative to a magnetization direction of the second ferromagnetic layer at zero applied magnetic field, the second ferromagnetic layer comprising first and second ferromagnetic films antiferromagnetically coupled to one another and an antiferromagnetically coupling film located between and in contact with the first and second ferromagnetic films for coupling the first and second ferromagnetic films together antiferromagnetically so that their magnetizations are aligned and remain antiparallel with one another in the presence of a magnetic field signal, the magnetization of the first ferromagnetic layer being freely rotatable in response to the magnetic field signal; and

a nonmagnetic high-conductivity layer disposed in contact with the first ferromagnetic layer so that the first ferromagnetic layer is disposed between the nonmagnetic spacer layer and the nonmagnetic high-conductivity layer,

wherein the nonmagnetic high-conductivity layer and the second ferromagnetic layer have a film thickness so that wave asymmetry, (V1−

V2)/(V1+V2), is in the range of negative 0.1 and positive 0.1, in which V1 is the peak value of reproduction output in a positive magnetic field signal and V2 is the peak value of reproduction output in a negative magnetic field signal.

2. The magnetoresistance effect element of claim 1, wherein the first ferromagnetic layer has a film thickness between 0.5 nanometers and 4.5 nanometers.

7. The magnetoresistance effect element of claim 1, wherein the nonmagnetic high-conductivity layer contains a metal element selected from the group consisting of copper (Cu) , gold (Au), silver (Ag), ruthenium (Ru), iridium (Ir), rhenium (Re), rhodium(Rh), platinum (Pt), palladium (Pd), aluminium (Al), osmium (Os), and nickel (Ni).

8. The magnetoresistance effect element of claim 1, wherein the first ferromagnetic layer includes a laminate film, and the laminate film comprises a layer containing nickel iron (NiFe) alloy and a layer containing cobalt (Co).

9. The magnetoresistance effect element of claim 1, wherein the first ferromagnetic layer contains cobalt iron (CoFe) alloy.

10. The magnetoresistance effect element of claim 1, wherein the nonmagnetic spacer layer contains copper (Cu) and the nonmagnetic spacer layer has a film thickness between 1.5 nanometers and 2.5 nanometers.

3. A magnetoresistance effect element, comprising:

a nonmagnetic spacer layer;

first and second ferromagnetic layers separated by the nonmagnetic spacer layer, the first ferromagnetic layer having a magnetization direction at an angle relative to a magnetization direction of the second ferromagnetic layer at zero applied magnetic field, the second ferromagnetic layer comprising first and second ferromagnetic films antiferromagnetically coupled to one another and an antiferromagnetically coupling film located between and in contact with the first and second ferromagnetic films for coupling the first and second ferromagnetic films together antiferromagnetically so that their magnetizations are aligned and remain antiparallel with one another in the presence of a magnetic field signal, the magnetization of the first ferromagnetic layer being freely rotatable in response to the magnetic field signal; and

a nonmagnetic high-conductivity layer disposed in contact with the first ferromagnetic layer so that the first ferromagnetic layer is disposed between the nonmagnetic spacer layer and the nonmagnetic high-conductivity layer,

wherein the first ferromagnetic layer responses to a magnetic field Hin of interlayer coupling between the first and second ferromagnetic layers, a stray magnetic field Hpin of second ferromagnetic layer, and a current magnetic field Hcu of electric current applied to the first ferromagnetic layer, and a sum of Hpin, Hin, and Hcu is substantially zero in center of film thickness of the first ferromagnetic layer.

4. A magnetoresistance effect element, comprising:

a nonmagnetic spacer layer;

first and second ferromagnetic layers separated by the nonmagnetic spacer layer, the first ferromagnetic layer having a magnetization direction at an angle relative to a magnetization direction of the second ferromagnetic layer at zero applied magnetic field, the second ferromagnetic layer comprising first and second ferromagnetic films antiferromagnetically coupled to one another and an antiferromagnetically coupling film located between and in contact with the first and second ferromagnetic films for coupling the first and second ferromagnetic films together antiferromagnetically so that their magnetizations are aligned and remain antiparallel with one another in the presence of a magnetic field signal, the magnetization of the first ferromagnetic layer being freely rotatable in response to the magnetic field signal; and

a nonmagnetic high-conductivity layer disposed in contact with the first ferromagnetic layer so that the first ferromagnetic layer is disposed between the nonmagnetic spacer layer and the nonmagnetic high-conductivity layer,

wherein the second ferromagnetic film is disposed adjacent to the nonmagnetic spacer layer via the first ferromagnetic film, the nonmagnetic high-conductivity layer has a film thickness t (HCL) in terms of copper (Cu) layer of specific resistance 10 microohm centimeter,

the first and second ferromagnetic films have a magnetic film thickness tm (pin1) and tm(pin2), respectively, in terms of saturation magnetization of 1 Tesla, and

t(HCL), tm (pin1) and tm(pin2) satisfy conditions of 0.5 nanometers<

tm(pin1)−

tm) (pin2)+t(HCL)<

4 nanometers and t(HCL)>

0.5 nanometers.

5. A magnetoresistance effect element, comprising:

a nonmagnetic spacer layer;

first and second ferromagnetic layers separated by the nonmagnetic spacer layer, the first ferromagnetic layer having a magnetization direction at an angle relative to a magnetization direction of the second ferromagnetic layer at zero applied magnetic field, the second ferromagnetic layer comprising first and second ferromagnetic films antiferromagnetically coupled to one another and an antiferromagnetically coupling film located between and in contact with the first and second ferromagnetic films for coupling the first and second ferromagnetic films together antiferromagnetically so that their magnetizations are aligned and remain antiparallel with one another in the presence of a magnetic field signal, the magnetization of the first ferromagnetic layer being freely rotatable in response to the magnetic field signal; and

a nonmagnetic high-conductivity layer disposed in contact with the first ferromagnetic layer so that the first ferromagnetic layer is disposed between the nonmagnetic spacer layer and the nonmagnetic high-conductivity layer,

wherein the nonmagnetic high-conductivity layer is formed of a material having a bulk resistivity at room temperature not larger than 10 microohm centimeter.

19. The magnetoresistance effect element of claim 5, wherein the first ferromagnetic layer has a film thickness between 0.5 nanometers and 4.5 nanometers.

20. The magnetoresistance effect element of claim 5, wherein the nonmagnetic high-conductivity layer contains a metal element selected from the group consisting of copper (Cu), gold (Au), silver (Ag), ruthenium (Ru), iridium (Ir), rhenium (Re), rhodium(Rh), platinum (Pt), palladium (Pd), aluminium (Al), osmium (Os), and nickel (Ni).

21. The magnetoresistance effect element of claim 5, wherein the first ferromagnetic layer includes a laminate film, and the laminate film comprises a layer containing nickel iron (NiFe) alloy and a layer containing cobalt (Co).

22. The magnetoresistance effect element of claim 5, wherein the first ferromagnetic layer contains cobalt iron (CoFe) alloy.

23. The magnetoresistance effect element of claim 5, wherein the nonmagnetic spacer layer contains copper (Cu) and the nonmagnetic spacer layer has a film thickness between 1.5 nanometers and 2.5 nanometers.

6. A magnetoresistance effect element, comprising:

a nonmagnetic spacer layer;

first and second ferromagnetic layers separated by the nonmagnetic spacer layer, the first ferromagnetic layer having a magnetization direction at an angle relative to a magnetization direction of the second ferromagnetic layer at zero applied magnetic field, the second ferromagnetic layer comprising first and second ferromagnetic films antiferromagnetically coupled to one another and an antiferromagnetically coupling film located between and in contact with the first and second ferromagnetic films for coupling the first and second ferromagnetic films together antiferromagnetically so that their magnetizations are aligned and remain antiparallel with one another in the presence of a magnetic field signal, the magnetization of the first ferromagnetic layer being freely rotatable in response to the magnetic field signal; and

a nonmagnetic high-conductivity layer disposed in contact with the first ferromagnetic layer so that the first ferromagnetic layer is disposed between the nonmagnetic spacer layer and the nonmagnetic high-conductivity layer,

wherein the nonmagnetic high-conductivity layer is formed of a material having a resistivity so that a substantially large number of majority carriers having a spin parallel to the magnetization direction of the first ferromagnetic layer exist in the nonmagnetic high-conductivity layer.

11. A magnetoresistance effect element, comprising:

a nonmagnetic spacer layer;

first and second ferromagnetic layers separated by the nonmagnetic spacer layer, the first ferromagnetic layer having a magnetization direction at an angle relative to a magnetization direction of the second ferromagnetic layer at zero applied magnetic field, the second ferromagnetic layer comprising first and second ferromagnetic films antiferromagnetically coupled to one another and an antiferromagnetically coupling film located between and in contact with the first and second ferromagnetic films for coupling the first and second ferromagnetic films together antiferromagnetically so that their magnetizations are aligned and remain antiparallel with one another in the presence of a magnetic field signal, the magnetization of the first ferromagnetic layer being freely rotatable in response to the magnetic field signal; and

a nonmagnetic high-conductivity layer disposed in contact with the first ferromagnetic layer so that the first ferromagnetic layer is disposed between the nonmagnetic spacer layer and the nonmagnetic high-conductivity layer,

wherein one of the first and second ferromagnetic films disposed adjacent to the nonmagnetic spacer layer has a film thickness equal to or thicker than another one of the first and second ferromagnetic films, and a difference in magnetic thickness between the first and second ferromagnetic films falls between 0 nanometers Tesla and 3 nanometers Tesla.

24. The magnetoresistance effect element of claim 11, wherein the first ferromagnetic layer has a film thickness between 0.5 nanometers and 4.5 nanometers.

25. The magnetoresistance effect element of claim 11, wherein the nonmagnetic high-conductivity layer contains a metal element selected from the group consisting of copper (Cu), gold (Au), silver (Ag), ruthenium (Ru), iridium (Ir), rhenium (Re), rhodium(Rh), platinum (Pt), palladium (Pd), aluminium (Al), osmium (Os), and nickel (Ni).

26. The magnetoresistance effect element of claim 11, wherein the first ferromagnetic layer includes a laminate film, and the laminate film comprises a layer containing nickel iron (NiFe) alloy and a layer containing cobalt (Co).

27. The magnetoresistance effect element of claim 11, wherein the first ferromagnetic layer contains cobalt iron (CoFe) alloy.

28. The magnetoresistance effect element of claim 11, wherein the nonmagnetic spacer layer contains copper (Cu) and the nonmagnetic spacer layer has a film thickness between 1.5 nanometers and 2.5 nanometers.

12. A magnetoresistance effect element, comprising:

a nonmagnetic spacer layer, first and second ferromagnetic layers separated by the nonmagnetic spacer layer, the first ferromagnetic layer having a magnetization direction at an angle relative to a magnetization direction of the second ferromagnetic layer at zero applied magnetic field, the magnetization of the first ferromagnetic layer freely rotating in response to a magnetic field signal; and

a nonmagnetic high-conductivity layer disposed in contact with the first ferromagnetic layer so that the first ferromagnetic layer is disposed between the nonmagnetic spacer layer and the nonmagnetic high-conductivity layer, wherein

the nonmagnetic high-conductivity layer and the second ferromagnetic layer have a respective film thickness so that wave asymmetry, (V1−

V2)/(V1+V2), is in the range of negative 0.1 and positive 0.1, in which V1 is the peak value of reproduction output in a positive magnetic field signal and V2 is the peak value of reproduction output in a negative magnetic field signal.

13. The magnetoresistance effect element of claim 12, wherein the first ferromagnetic layer has a film thickness between 0.5 nanometers and 4.5 nanometers.

14. The magnetoresistance effect element of claim 12, wherein the nonmagnetic high-conductivity layer has a film thickness t (HCL) in terms of copper (Cu) layer of specific resistance 10 microohm centimeter, the second ferromagnetic layer has a magnetic film thickness tm (pin1) in terms of saturation magnetization of 1 T and the t (HCL) and tm (pin1) satisfy conditions of 0.5 nanometers≦

tm (pin1)+t (HCL)≦

4 nanometers and t (HCL)≧

0.5 nanometers.

15. The magnetoresistance effect element of claim 12, wherein the second ferromagnetic film is disposed adjacent to the nonmagnetic spacer layer via the first ferromagnetic film, the second ferromagnetic layer comprises first and second ferromagnetic films antiferromagnetically coupled to one another and an antiferromagnetically coupling film located between and in contact with the first and second ferromagnetic films for coupling the first and second ferromagnetic films together antiferromagnetically,

the nonmagnetic high-conductivity layer has a film thickness t (HCL) in terms of copper (Cu) layer of specific resistance 10 microohm centimeter,

the first and the second ferromagnetic films have a magnetic film thickness tm(pin1) and tm(pin2), respectively, in terms of saturation magnetization of 1 Tesla and, t (HCL), tm (pin1), and tm (pin2) satisfy conditions of 0.5 nanometers≦ tm (pin1)−

tm (pin2)+t (HCL)≦

4 nanometers and t (HCL)≧

0.5 nanometers.

16. A magnetoresistance effect element, comprising:

a nonmagnetic spacer layer,

first and second ferromagnetic layers separated by the nonmagnetic spacer layer, the first ferromagnetic layer has a magnetization direction of the first ferromagnetic layer at an angle relative to a magnetization direction of the second ferromagnetic layer at zero applied magnetic field, the magnetization of the first ferromagnetic layer freely rotating in a magnetic field signal; and

a nonmagnetic high-conductivity layer disposed in contact with the first ferromagnetic layer so that the first ferromagnetic layer is disposed between the nonmagnetic spacer layer and the nonmagnetic high-conductivity layer, wherein

the nonmagnetic high-conductivity layer has a film thickness t (HCL) in terms of Cu layer of specific resistance 10 microohm centimeter, the pair of ferromagnetic films have a magnetic film thickness tm (pin1) in terms of saturation magnetization of 1 Tesla and t (HCL) and tm (pin1) satisfy conditions of 0.5 nanometers≦

tm (pin1)+t (HCL)≦

4 nanometers and t(HCL)≧

0.5 nanometers.

17. The magnetoresistance effect element of claim 16, wherein the nonmagnetic high-conductivity layer contains a metal element selected from the group consisting of copper (Cu), gold (Au), silver (Ag), ruthenium (Ru), iridium (Ir), rhenium (Re), rhodium (Rh), platinum (Pt), palladium (Pd), aluminium (Al), osmium (Os), and nickel (Ni).

18. A magnetoresistance effect element, comprising:

a nonmagnetic spacer layer,

first and second ferromagnetic layers separated by the nonmagnetic spacer layer, the first ferromagnetic layer has a magnetization direction at an angle relative to a magnetization direction of the second ferromagnetic layer at zero applied magnetic field, the second ferromagnetic layer comprising first and second ferromagnetic films antiferromagnetically coupled to one another and an antiferromagnetically coupling film located between and in contact with the first and second ferromagnetic films for coupling the first and second ferromagnetic films together antiferromagnetically so that their magnetizations are aligned antiparallel with one another and remain antiparallel in the presence of an applied magnetic field, the magnetization of the first ferromagnetic layer freely rotating in signal magnetic field; and

an antiferromagnetic layer disposed in contact and exchange coupled with one of the ferromagnetic films, a closed packed plane of the antiferromagnetic layer being oriented so that a half-value width of the diffraction peak from the close-packed plane of the antiferromagnetic layer in its rocking curve is 8 or less.

29. The magnetoresistance effect element of claim 18, wherein the total thickness of the first and second ferromagnetic layers and the magnetic spacer layer is 14 nm or below.

30. The magnetoresistance effect element of claim 18, wherein the first ferromagnetic layer is between 2 nm and 5 nm in thickness.

31. The magnetoresistance effect element of claim 18, further comprising:

a magnetic gap layer; and

a layer disposed between the magnetic gap layer and one of the first ferromagnetic layer and the antiferromagnetic layer, the layer made of a material selected from a group consisting of NiFe, NiCu, NiFeCr, and NiFeTa.

32. The magnetoresistance effect element of claim 18, wherein the antiferromagnetic layer contains PtMn or PtPdMn.

33. The magnetoresistance effect element of claim 18, wherein the antiferromagnetic layer contains IrMn, PhMn or RhRuMn.

34. The magnetoresistance effect element of claim 18, wherein the antiferromagnetically coupling film contains Ru, and has a thickness of 0.8-1.21 nm.

35. The magnetoresistance effect element of claim 18, further comprising a longitudinal bias layer that includes an antiferromagnetic film.