Hasegawa, Naoya (Niigata-ken, JP)
Ide, Yosuke (Niigata-ken, JP)
Tanaka, Kenichi (Niigata-ken, JP)
What is claimed is:
1. A method of producing an exchange coupling film comprising an antiferromagnetic layer, a ferromagnetic layer, contacting said antiferromagnetic layer at an interface therebetween, and a seed layer comprising a (111) plane of face-centered cubic crystal, which seed layer contacts said antiferromagnetic layer at an interface therebetween on a side opposite said ferromagnetic layer, said method comprising: forming said seed layer such that said (111) plane of face-centered cubic crystal is preferentially oriented in a direction parallel to said interface between said seed layer and said antiferromagnetic layer, thereby creating a non-aligned state at at least a part of said interface between said antiferromagnetic layer and said seed layer; and effecting a heat-treatment after said forming, so as to develop an exchange coupling magnetic field at said interface between said antiferromagnetic layer and said ferromagnetic layer.
2. A method of producing an exchange coupling film comprising an antiferromagnetic layer, a ferromagnetic layer, contacting said antiferromagnetic layer at an interface therebetween, and a seed layer comprising a (111) plane of face-centered cubic crystal, which seed layer contacts said antiferromagnetic layer at an interface therebetween on a side opposite to said ferromagnetic layer, said method comprising: forming said seed layer such that said (111) plane of face-centered cubic crystal is preferentially oriented in a direction parallel to said interface between said seed layer and said antiferromagnetic layer, thereby creating a difference in lattice constant between said antiferromagnetic layer and said seed layer at at least a part of said interface between said antiferromagnetic layer and said seed layer; and effecting a heat-treatment after said forming, so as to develop an exchange coupling magnetic field at said interface between said antiferromagnetic layer and said ferromagnetic layer.
3. The method of claim 2, wherein a non-aligned state is created at at least a part of said interface between said antiferromagnetic layer and said seed layer.
4. The method of claim 1, wherein said antiferromagnetic layer comprises an element X and Mn, wherein X is selected from the group consisting of Pt, Pd, Ir, Rh, Ru, Os, and combinations thereof.
5. The method of claim 2, wherein said antiferromagnetic layer comprises an element X and Mn, wherein X is selected from the group consisting of Pt, Pd, Ir, Rh, Ru, Os, and combinations thereof.
6. The method of claim 1, wherein said antiferromagnetic layer comprises an element X, an element X′ and Mn, wherein X is selected from the group consisting of Pt, Pd, Ir, Rh, Ru, Os, and combinations thereof, and X′ is selected from the group consisting of Ne, Ar, Kr, Xe, Be, B, C, N, Mg, Al, Si, P, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, Cd, Sn, Hf, Ta, W, Re, Au, Pb, a rare earth element, and combinations thereof.
7. The method of claim 2, wherein said antiferromagnetic layer comprises an element X, an element X′ and Mn, wherein X is selected from the group consisting of Pt, Pd, Ir, Rh, Ru, Os, and combinations thereof, and X′ is selected from the group consisting of Ne, Ar, Kr, Xe, Be, B, C, N, Mg, Al, Si, P, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, Cd, Sn, Hf, Ta, W, Re, Au, Pb, a rare earth element, and combinations thereof.
8. A method of producing an exchange coupling film comprising an antiferromagnetic layer, a ferromagnetic layer contacting said antiferromagnetic layer at an interface therebetween, and a seed layer comprising a (111) plane of face-centered crystal, which seed layer contacts said antiferromagnetic layer at an interface therebetwen on a side opposite said ferromagnetic layer, said method comprising: forming said seed layer such that said (111) plane of face-centered cubic crystal is preferentially oriented in a direction parallel to said interface between said seed layer and said antiferromagnetic layer; depositing on said seed layer an antiferromagnetic layer comprising an element X and Mn, wherein X is selected from the group consisting of Pt, Pd, Ir, Rh, Ru, Os, and combinations thereof, elevating a sputtering gas pressure during said depositing so that a composition ratio of said element X in said antiferromagnetic layer progressively decreases as distance from said seed layer increases; decreasing said sputtering gas pressure during said depositing so that said composition ratio of said element X in said antiferromagnetic layer progressively increases as distance from said seed layer further increases; and effecting a heat-treatment after said forming and said depositing, so as to develop an exchange coupling magnetic field at said interface between said antiferromagnetic layer and said ferromagnetic layer.
9. A method of producing an exchange coupling film comprising an antiferromagnetic layer, a ferromagnetic layer contacting said antiferromagnetic layer at an interface therebetween, and a seed layer comprising a (111) plane of face-centered cubic crystal, which seed layer contacts said antiferromagnetic layer at an interface therebetween on a side opposite said ferromagnetic layer, said method comprising: forming said seed layer such that the (111) plane of face-centered cubic crystal is preferentially oriented in a direction parallel to said interface between said seed layer and said antiferromagnetic layer; depositing on said seed layer, an antiferromagnetic layer comprising an element X, an element X′ and Mn, wherein X is selected from the group consisting of Pt, Pd, Ir, Rh, Ru, Os, and combinations thereof, and X′ is selected from the group consisting of Ne, Ar, Kr, Xe, Be, B, C, N, Mg, Al, Si, P, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, Cd, Sn, Hf, Ta, W, Re, Au, Pb, a rare earth element, and combinations thereof; elevating a sputtering gas pressure during said depositing so that a composition ratio of said elements X+X′ in said antiferromagnetic layer progressively decreases as distance from said seed layer increases; decreasing said sputtering gas pressure during said depositing so that said composition ratio of said elements X +X′ in said antiferromagnetic layer progressively increases as distance from said seed layer further increases; and effecting a heat-treatment after said forming and said depositing, so as to develop an exchange coupling magnetic field at said interface between said antiferromagnetic layer and said ferromagnetic layer.
10. The method of claim 8, wherein said composition ratio of element X in said antiferromagnetic layer to a total composition ratio of said antiferromagnetic layer is not less than 53 at % and not more than 65 at %, in a region near said interface between said antiferromagnetic layer and said ferromagnetic layer and in a region near said interface between said antiferromagnetic layer and said seed layer.
11. The method of claim 9, wherein said composition ratio of said elements X+X′ of said antiferromagnetic layer to a total composition ratio of said antiferromagnetic layer is not less than 53 at % and not more than 65 at %, in a region near said interface between said antiferromagnetic layer and said ferromagnetic layer and in a region near said interface between said antiferromagnetic layer and said seed layer.
12. The method of claim 10, wherein said composition ratio of said element X is not less than 55 at % and not greater than 60 at %.
13. The method of claim 11, wherein said composition ratio of said elements X+X′ is not less than 55 at % and not greater than 60 at %.
14. The method of claim 8, wherein said composition ratio of said element X is not less than 44 at % and not more than 57 at %, in a region near a thicknesswise central portion of said antiferromagnetic layer.
15. The method of claim 9, wherein said composition ratio of said elements X+X′ is not less than 44 at % and not more than 57 at %, in a region near a thicknesswise central portion of said antiferromagnetic layer.
16. The method of claim 10, wherein said composition ratio of said element X is not less than 44 at % and not more than 57 at %, in a region near a thicknesswise central portion of said antiferromagnetic layer.
17. The method of claim 11, wherein said composition ratio of said elements X+X′ is not less than 44 at % and not more than 57 at %, in a region near a thicknesswise central portion of said antiferromagnetic layer.
18. The method of claim 12, wherein said composition ratio of said element X is not less than 44 at % and not more than 57 at %, in a region near a thicknesswise central portion of said antiferromagnetic layer.
19. The method of claim 13, wherein said composition ratio of said elements X+X′ is not less than 44 at % and not more than 57 at %, in a region near a thicknesswise central portion of said antiferromagnetic layer.
20. The method of claim 14, wherein said composition ratio of said element X is not less than 46 at % and not more than 55 at %.
21. The method of claim 15, wherein said composition ratio of said elements X+X′ is not less than 46 at % and not more than 55 at %.
22. The method of claim 16, wherein said composition ratio of said element X is not less than 46 at % and not more than 55 at %.
23. The method of claim 17, wherein said composition ratio of said elements X+X′ is not less than 46 at % and not more than 55 at %.
24. The method of claim 18, wherein said composition ratio of said element X is not less than 46 at % and not more than 55 at %.
25. The method of claim 19, wherein said composition ratio of said elements X+X′ is not less than 46 at % and not more than 55 at %.
26. The method of claim 8, wherein said antiferromagnetic layer has a thickness not smaller than 76 Å.
27. The method of claim 9, wherein said antiferromagnetic layer has a thickness not smaller than 76 Å.
28. A method of producing an exchange coupling film comprising an antiferromagnetic layer, a ferromagnetic layer contacting said antiferromagnetic layer at an interface therebetween, and a seed layer comprising a (111) plane of face-centered cubic crystal, which said layer contacts said antiferromagnetic layer at an interface therebetween on a side opposite said ferromagnetic layer, said antiferromagnetic layer comprising a first antiferromagnetic layer, a second antiferromagnetic layer and a third antiferromagnetic layer said method comprising: forming said seed layer such that said (111) plane of face-centered cubic crystal is preferentially oriented in a direction parallel to said interface between said seed layer and said antiferromagnetic layer; forming said antiferromagnetic layer such that said third antiferromagnetic layer is adjacent to said seed layer, said first antiferromagnetic layer is adjacent to said ferromagnetic layer, and said second antiferromagnetic layer is between said first and said third antiferromagnetic layers, wherein each of said first, said second, and said third antiferromagnetic layers comprise an element X and Mn, wherein X is selected from the group consisting of Pt, Pd, Ir, Rh, Ru, Os, and combinations thereof, such that said second antiferromagnetic layer has a smaller composition ratio of said element X than said first and said second antiferromagnetic layers; and effecting a heat-treatment after said forming of said seed layer and said forming of said antiferromagnetic layer, such that an exchange coupling magnetic field is developed at said interface between said antiferromagnetic layer and said ferromagnetic layer.
29. A method of producing an exchange coupling film comprising an antiferromagnetic layer, a ferromagnetic layer contacting said antiferromagnetic layer at an interface therebetween, and a seed layer comprising a (111) plane of face-centered cubic crystal, which seed layer contacts said antiferromagnetic layer at an interface therebetween on a side opposite said ferromagnetic layer, said antiferromagnetic layer comprising a first antiferromagnetic layer, a second antiferromagnetic layer, and a third antiferromagnetic layer said method comprising: forming said seed layer such that said (111) plane of face-centered cubic crystal is preferentially oriented in a direction parallel to said interface between said seed layer and said antiferromagnetic layer; forming said antiferromagnetic layer such that said third antiferromagnetic layer is adjacent to said seed layer, said first antiferromagnetic layer is adjacent to said ferromagnetic layer, and said second antiferromagnetic layer is between said first and said third antiferromagnetic layer, wherein each of said first, said second, and said third antiferromagnetic layers comprise an element X, an element X′ and Mn, wherein X is selected from the group consisting of Pt, Pd, Ir, Rh, Ru, Os, and combinations thereof, and X′ is selected from the group consisting of Ne, Ar, Kr, Xe, Be, B, C, N, Mg, Al, Si, P, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, Cd, Sn, Hf, Ta, W, Re, Au, Pb, a rare earth element, and combinations thereof, such that said second antiferromagnetic layer has a smaller composition ratio of said element X than said first and said second antiferromagnetic layers; and effecting a heat-treatment after said forming of said seed layer and said forming of said antiferromagnetic layer, such that an exchange coupling magnetic field is developed at said interface between said antiferromagnetic layer and said ferromagnetic layer.
30. The method of claim 8, wherein a difference in lattice constant is created between said antiferromagnetic layer and said seed layer at at least a part of said interface between said antiferromagnetic layer and said seed layer.
31. The method of claim 9, wherein a difference in lattice constant is created between said antiferromagnetic layer and said seed layer at at least a part of said interface between said antiferromagnetic layer and said seed layer.
32. The method of claim 28, wherein a difference in lattice constant is created between said antiferromagnetic layer and said seed layer at at least a part of said interface between said antiferromagnetic layer and said seed layer.
33. The method of claim 29, wherein a difference in lattice constant is created between said antiferromagnetic layer and said seed layer at at least a part of said interface between said antiferromagnetic layer and said seed layer.
34. The method of claim 8, wherein a non-aligned state is created at at least a part of said interface between said antiferromagnetic layer and said seed layer.
35. The method of claim 9, wherein a non-aligned state is created at at least a part of said interface between said antiferromagnetic layer and said seed layer.
36. The method of claim 28, wherein a non-aligned state is created at at least a part of said interface between said antiferromagnetic layer and said seed layer.
37. The method of claim 29, wherein a non-aligned state is created at at least a part of said interface between said antiferromagnetic layer and said seed layer.
38. The method of claim 6, wherein said element X′ is selected from the group consisting of an element which invades interstices of a space lattice composed of said element X and said Mn, and an element which substitutes for a portion of lattice points of a crystalline lattice constituted by said Mn and said element X.
39. The method of claim 7, wherein said element X′ is selected from the group consisting of an element which invades interstices of a space lattice composed of said element X and said Mn, and an element which substitutes for a portion of lattice points of a crystalline lattice constituted by said Mn and said element X.
40. The method of claim 9, wherein said element X′ is selected from the group consisting of an element which invades interstices of a space lattice composed of said element X and said Mn, and an element which substitutes for a portion of lattice points of a crystalline lattice constituted by said Mn and said element X.
41. The method of claim 29, wherein said element X′ is selected from the group consisting of an element which invades interstices of a space lattice composed of said element X and said Mn, and an element which substitutes for a portion of lattice points of a crystalline lattice constituted by said Mn and said element X.
42. The method of claim 28, wherein said composition ratio of said element X in each of said first and said third antiferromagnetic layer is not less than 53 at % and but not more than 65 at %.
43. The method of claim 29, wherein a composition ratio of said elements X+X′ of each of said first and said third antiferromagnetic layer is not less than 53 at % and not more than 65 at %.
44. The method of claim 28, wherein said composition ratio of said element X is not less than 55 at % and not more than 60 at %.
45. The method of claim 29, wherein a composition ratio of said elements X+X′ is not less than 55 at % and not more than 60 at %.
46. The method of claim 28, wherein said composition ratio of said element X of said second antiferromagnetic layer is not less than 44 at % and not more than 57 at %.
47. The method of claim 29, wherein a composition ratio of said elements X+X′ of said second antiferromagnetic layer is not less than 44 at % and not more than 57 at %.
48. The method of claim 42, wherein said composition ratio of said element X of said second antiferromagnetic layer is not less than 44 at % and not more than 57 at %.
49. The method of claim 43, wherein said composition ratio of said elements X+X′ of said second antiferromagnetic layer is not less than 44 at % and not more than 57 at %.
50. The method of claim 44, wherein said composition ratio of said element X of said second antiferromagnetic layer is not less than 44 at % and not more than 57 at %.
51. The method of claim 45, wherein said composition ratio of the elements X+X′ of the second antiferromagnetic layer is not less than 44 (at %) but not more than 57 (at %).
52. The method of claim 46, wherein said composition ratio of the element X is not less than 46 at % and not more than 55 at %.
53. The method of claim 47, wherein said composition ratio of said elements X+X′ is not less than 46 at % and not more than 55 at %.
54. The method of claim 48, wherein said composition ratio of said element X is not less than 46 at % and not more than 55 at %.
55. The method of claim 49, wherein said composition ratio of said elements X+X′ is not less than 46 at % and not more than 55 at %.
56. The method of claim 50, wherein said composition ratio of said element X is not less than 46 at % and not more than 55 at %.
57. The method of claim 51, wherein said composition ratio of said elements X+X′ is not less than 46 at % and not more than 55 at %.
58. The method of claim 28, wherein each of said first and said third antiferromagnetic layers has a thickness not smaller than 3 Å and not greater than 30 Å.
59. The method of claim 29, wherein each of said first and said third antiferromagnetic layers has a thickness not smaller than 3 Å and not greater than 30 Å.
60. The method of claim 28, wherein said second antiferromagnetic layer has a thickness of 70 Å or greater.
61. The method of claim 29, wherein said second antiferromagnetic layer has a thickness of 70 Å or greater.
62. The method of claim 58, wherein said second antiferromagnetic layer has a thickness of 70 Å or greater.
63. The method of claim 59, wherein said second antiferromagnetic layer has a thickness of 70 Å or greater.
64. The method of claim 1, wherein said antiferromagnetic layer and said ferromagnetic layer have different lattice constants at at least a part of said interface therebetween.
65. The method of claim 2, wherein said antiferromagnetic layer and said ferromagnetic layer have different lattice constants at at least a part of said interface therebetween.
66. The method of claim 8, wherein said antiferromagnetic layer and said ferromagnetic layer have different lattice constants at at least a part of said interface therebetween.
67. The method of claim 9, wherein said antiferromagnetic layer and said ferromagnetic layer have different lattice constants at at least a part of said interface therebetween.
68. The method of claim 28, wherein said antiferromagnetic layer and said ferromagnetic layer have different lattice constants at at least a part of said interface therebetween.
69. The method of claim 29, wherein said antiferromagnetic layer and said ferromagnetic layer have different lattice constants at at least a part of said interface therebetween.
70. The method of claim 1, wherein a non-aligned state is created at at least a part of said interface between said antiferromagnetic layer and said ferromagnetic layer.
71. The method of claim 2, wherein a non-aligned state is created at at least a part of said interface between said antiferromagnetic layer and said ferromagnetic layer.
72. The method of claim 8, wherein a non-aligned state is created at at least a part of said interface between said antiferromagnetic layer and said ferromagnetic layer.
73. The method of claim 9, wherein a non-aligned state is created at at least a part of said interface between said antiferromagnetic layer and said ferromagnetic layer.
74. The method of claim 28, wherein a non-aligned state is created at at least a part of said interface between said antiferromagnetic layer and said ferromagnetic layer.
75. The method of claim 29, wherein a non-aligned state is created at at least a part of said interface between said antiferromagnetic layer and said ferromagnetic layer.
76. The method of claim 1, wherein said seed layer comprises an alloy selected from the group consisting of a Ni—Fe alloy and a Ni—Fe—Y alloy, wherein Y is selected from the group consisting of Cr, Rh, Ta, Hf, Nb, Zr, Ti, and combinations thereof.
77. The method of claim 2, wherein said seed layer comprises an alloy selected from the group consisting of a Ni—Fe alloy and a Ni—Fe—Y alloy, wherein Y is selected from the group consisting of Cr, Rh, Ta, Hf, Nb, Zr, Ti, and combinations thereof.
78. The method of claim 8, wherein said seed layer comprises an alloy selected from the group consisting of a Ni—Fe alloy and a Ni—Fe—Y alloy, wherein Y is selected from the group consisting of Cr, Rh, Ta, Hf, Nb, Zr, Ti, and combinations thereof.
79. The method of claim 9, wherein said seed layer comprises an alloy selected from the group consisting of a Ni—Fe alloy and a Ni—Fe—Y alloy, wherein Y is selected from the group consisting of Cr, Rh, Ta, Hf, Nb, Zr, Ti, and combinations thereof.
80. The method of claim 28, wherein said seed layer comprises an alloy selected from the group consisting of a Ni—Fe alloy and a Ni—Fe—Y alloy, wherein Y is selected from the group consisting of Cr, Rh, Ta, Hf, Nb, Zr, Ti, and combinations thereof.
81. The method of claim 29, wherein said seed layer comprises an alloy selected from the group consisting of a Ni—Fe alloy and a Ni—Fe—Y alloy, wherein Y is selected from the group consisting of Cr, Rh, Ta, Hf, Nb, Zr, Ti, and combinations thereof.
82. The method of claim 1, wherein said seed layer is non-magnetic.
83. The method of claim 2, wherein said seed layer is non-magnetic.
84. The method of claim 8, wherein said seed layer is non-magnetic.
85. The method of claim 9, wherein said seed layer is non-magnetic.
86. The method of claim 28, wherein said seed layer is non-magnetic.
87. The method of claim 29, wherein said seed layer is non-magnetic.
88. The method of claim 1, wherein said exchange coupling film further comprises an underlying layer, which comprises an element selected from the group consisting of Ta, Hf, Nb, Zr, Ti, Mo, W, and combinations thereof, and wherein said seed layer is adjacent to said underlying layer.
89. The method of claim 2, wherein said exchange coupling film further comprises an underlying layer, which comprises an element selected from the group consisting of Ta, Hf, Nb, Zr, Ti, Mo, W, and combinations thereof, and wherein said seed layer is adjacent to said underlying layer.
90. The method of claim 8, wherein said exchange coupling film further comprises an underlying layer, which comprises an element selected from the group consisting of Ta, Hf, Nb, Zr, Ti, Mo, W, and combinations thereof, and wherein said seed layer is adjacent to said underlying layer.
91. The method of claim 9, wherein said exchange coupling film further comprises an underlying layer, which comprises an element selected from the group consisting of Ta, Hf, Nb, Zr, Ti, Mo, W, and combinations thereof, and wherein said seed layer is adjacent to said underlying layer.
92. The method of claim 28, wherein said exchange coupling film further comprises an underlying layer, which comprises an element selected from the group consisting of Ta, Hf, Nb, Zr, Ti, Mo, W, and combinations thereof, and wherein said seed layer is adjacent to said underlying layer.
93. The method of claim 29, wherein said exchange coupling film further comprises an underlying layer, which comprises an element selected from the group consisting of Ta, Hf, Nb, Zr, Ti, Mo, W, and combinations thereof, and wherein said seed layer is adjacent to said underlying layer.
94. A method of producing a magnetoresistive sensor comprising an antiferromagnetic layer, a seed layer contacting said antiferromagnetic layer at an interface therebetween, a pinned magnetic layer contacting said antiferromagnetic layer at an interface therebetween which has a direction of magnetization fixed by an exchange anisotropic magnetic field with said antiferromagnetic layer, a non-magnetic intermediate layer between said pinned magnetic layer and a free magnetic layer, and a bias layer which aligns a direction of magnetization of said free magnetic layer in a direction that intersects said direction of magnetization of said pinned magnetic layer, said method comprising: forming said antiferromagnetic layer, said pinned magnetic layer and said seed layer by the method of claim 1.
95. A method of producing a magnetoresistive sensor comprising an antiferromagnetic layer, a seed layer contacting said antiferromagnetic layer at an interface therebetween, a pinned magnetic layer contacting said antiferromagnetic layer at an interface between which has a direction of magnetization fixed by an exchange anisotropic magnetic field with said antiferromagnetic layer, a non-magnetic intermediate layer between said pinned magnetic layer and a free magnetic layer, and a bias layer which aligns a direction of magnetization of said free magnetic layer in a direction that intersects said direction of magnetization of said pinned magnetic layer, said method comprising: forming said antiferromagnetic layer, said pinned magnetic layer and said seed layer by the method of claim 2.
96. A method of producing a magnetoresistive sensor comprising an antiferromagnetic layer, a seed layer contacting said antiferromagnetic layer at an interface therebetween, a pinned magnetic layer contacting said antiferromagnetic layer at an interface therebetween which has a direction of magnetization fixed by an exchange anisotropic magnetic field with said antiferromagnetic layer, a non-magnetic intermediate layer between said pinned magnetic layer and a free magnetic layer, and a bias layer which aligns a direction of magnetization of said free magnetic layer in a direction that intersects said direction of magnetization of said pinned magnetic layer, said method comprising: forming said antiferromagnetic layer, said pinned magnetic layer and said seed layer by the method of claim 8.
97. A method of producing a magnetoresistive sensor comprising an antiferromagnetic layer, a seed layer contacting said antiferromagnetic layer at an interface therebetween, a pinned magnetic layer contacting said antiferromagnetic layer at an interface therebetween which has a direction of magnetization fixed by an exchange anisotropic magnetic field with said antiferromagnetic layer, a non-magnetic intermediate layer between said pinned magnetic layer and a free magnetic layer, and a bias layer which aligns a direction of magnetization of said free magnetic layer in a direction that intersects said direction of magnetization of said pinned magnetic layer, said method comprising: forming said antiferromagnetic layer, said pinned magnetic layer and said seed layer by the method of claim 9.
98. A method of producing a magnetoresistive sensor comprising an antiferromagnetic layer, a seed layer contacting said antiferromagnetic layer at an interface therebetween, a pinned magnetic layer contacting said antiferromagnetic layer at an interface therebetween which has a direction of magnetization fixed by an exchange anisotropic magnetic field with said antiferromagnetic layer, a non-magnetic intermediate layer between said pinned magnetic layer and a free magnetic layer, and a bias layer which aligns a direction of magnetization of said free magnetic layer in a direction that intersects said direction of magnetization of said pinned magnetic layer, said method comprising: forming said antiferromagnetic layer, said pinned magnetic layer and said seed layer by the method of claim 28.
99. A method of producing a magnetoresistive sensor comprising an antiferromagnetic layer, a seed layer contacting said antiferromagnetic layer at an interface therebetween, a pinned magnetic layer contacting said antiferromagnetic layer at an interface therebetween which has a direction of magnetization fixed by an exchange anisotropic magnetic field with said antiferromagnetic layer, a non-magnetic intermediate layer between said pinned magnetic layer and a free magnetic layer, and a bias layer which aligns a direction of magnetization of said free magnetic layer in a direction that intersects said direction of magnetization of said pinned magnetic layer, said method comprising: forming said antiferromagnetic layer, said pinned magnetic layer and said seed layer by the method of claim 29.
100. A method of producing a magnetoresistive sensor comprising an antiferromagnetic layer, a seed layer contacting said antiferromagnetic layer at an interface therebetween, a pinned magnetic layer contacting said antiferromagnetic layer at an interface therebetween which has a direction of magnetization fixed by an exchange anisotropic magnetic field with said antiferromagnetic layer, a non-magnetic intermediate layer between said pinned magnetic layer and a free magnetic layer having an upper side and a lower side, and an antiferromagnetic exchange bias layer formed on either said upper side or said lower side of said free magnetic layer, said antiferromagnetic exchange bias layer comprising a plurality of portions spaced from each other in a track width direction, said method comprising: forming said exchange bias layer, said free magnetic layer and said seed layer by the method of claim 1.
101. A method of producing a magnetoresistive sensor comprising an antiferromagnetic layer, a seed layer contacting said antiferromagnetic layer at an interface therebetween, a pinned magnetic layer contacting said antiferromagnetic layer at an interface therebetween which has a direction of magnetization fixed by an exchange anisotropic magnetic field with said antiferromagnetic layer, a non-magnetic intermediate layer between said pinned magnetic layer and a free magnetic layer having an upper side and a lower side, and an antiferromagnetic exchange bias layer formed on either said upper side or said lower side of said free magnetic layer, said antiferromagnetic exchange bias layer comprising a plurality of portions spaced from each other in a track width direction, said method comprising: forming said exchange bias layer, said free magnetic layer and said seed layer by the method of claim 2.
102. A method of producing a magnetoresistive sensor comprising an antiferromagnetic layer, a seed layer contacting said antiferromagnetic layer at an interface therebetween, a pinned magnetic layer contacting said antiferromagnetic layer at an interface therebetween which has a direction of magnetization fixed by an exchange anisotropic magnetic field with said antiferromagnetic layer, a non-magnetic intermediate layer between said pinned magnetic layer and a free magnetic layer having an upper side and a lower side, and an antiferromagnetic exchange bias layer on either said upper side or said lower side of said free magnetic layer, said antiferromagnetic exchange bias layer comprising a plurality of portions spaced from each other in a track width direction, said method comprising: forming said exchange bias layer, said free magnetic layer and said seed layer by the method of claim 8.
103. A method of producing a magnetoresistive sensor comprising an antiferromagnetic layer, a seed layer contacting said antiferromagetic layer at an interface therebetween, a pinned magnetic layer contacting said antiferromagnetic layer at an interface therebetween which has a direction of magnetization fixed by an exchange anisotropic magnetic field with said antiferromagnetic layer, a non-magnetic intermediate layer between said pinned magnetic layer and a free magnetic layer having an upper side and a lower side, and an antiferromagnetic exchange bias layer on either said upper side or said lower side of said free magnetic layer, said antiferromagnetic exchange bias layer comprising a plurality of portions spaced from each other in a track width direction, said method comprising: forming said exchange bias layer, said free magnetic layer and said seed layer by the method of claim 9.
104. A method of producing a magnetoresistive sensor comprising an antiferromagnetic layer, a seed layer contacting said antiferromagnetic layer at an interface therebetween, a pinned magnetic layer contacting said antiferromagnetic layer at an interface therebetween which has a direction of magnetization fixed by an exchange anisotropic magnetic field with said antiferromagnetic layer, a non-magnetic intermediate layer between said pinned magnetic layer and a free magnetic layer having an upper side and a lower side, and an antiferromagnetic exchange bias layer on either said upper side or said lower side of said free magnetic layer, said antiferromagnetic exchange bias layer comprising a plurality of portions spaced from each other in a track width direction, said method comprising: forming said exchange bias layer, said free magnetic layer and said seed layer by the method of claim 28.
105. A method of producing a magnetoresistive sensor comprising an antiferromagnetic layer, a seed layer contacting said antiferromagnetic layer at an interface therebetween, a pinned magnetic layer contacting said antiferromagnetic layer at an interface therebetween which has a direction of magnetization fixed by an exchange anisotropic magnetic field with said antiferromagnetic layer, a non-magnetic intermediate layer between said pinned magnetic layer and a free magnetic layer having an upper side and a lower side, and an antiferromagnetic exchange bias layer formed on either said upper side or said lower side of said free magnetic layer, said antiferromagnetic exchange bias layer comprising a plurality of portions spaced from each other in a track width direction, said method comprising: forming said exchange bias layer, said free magnetic layer and said seed layer by the method of claim 29.
106. A method of producing a magnetoresistive sensor comprising a seed layer; a first antiferromagnetic layer overlying said seed layer; a first pinned magnetic layer overlying said first antiferromagnetic layer; a first non-magnetic layer overlying said first pinned magnetic layer; a free magnetic layer overlying said first non-magnetic layer, said free magnetic layer having an upper side and a lower side; a second non-magnetic layer overlying said free magnetic layer; a second pinned magnetic layer overlying said second non-magnetic layer; a second antiferromagnetic layer overlying said second pinned magnetic layer, said first and second antiferromagnetic layers serving to fix directions of magnetization of said first and said second pinned magnetic layers by exchange anisotropic magnetic fields; and a bias layer which aligns a direction of magnetization of said free magnetic layer to a direction that intersects said directions of said first and said second pinned magnetic layers, said method comprising: forming at least one of said first and said second antiferromagnetic layers at least one of said first and said second pinned magnetic layers, said seed layer, and at least one of said upper and said lower sides of said free magnetic layer, by the method of claim 1.
107. A method of producing a magnetoresistive sensor comprising a seed layer; a first antiferromagnetic layer overlying said seed layer; a first pinned magnetic layer overlying said first antiferromagnetic layer; a first non-magnetic layer overlying said first pinned magnetic layer; a free magnetic layer overlying said first non-magnetic layer, said free magnetic layer having an upper side and a lower side; a second non-magnetic layer overlying said free magnetic layer; a second pinned magnetic layer overlying said second non-magnetic layer; a second antiferromagnetic layer overlying said second pinned magnetic layer, said first and second antiferromagnetic layers serving to fix directions of magnetization of said first and said second pinned magnetic layers by exchange anisotropic magnetic fields; and a bias layer which aligns a direction of magnetization of said free magnetic layer to a direction that intersects said directions of said first and said second pinned magnetic layers, said method comprising: forming at least one of said first and said second antiferromagnetic layers at least one of said first and said second pinned magnetic layers said seed layer, and at least one of said upper and said lower sides of said free magnetic layer, by the method of claim 2.
108. A method of producing a magnetoresistive sensor comprising a seed layer; a first antiferromagnetic layer overlying said seed layer; a first pinned magnetic layer overlying said first antiferromagnetic layer; a first non-magnetic layer overlying said first pinned magnetic layer; a free magnetic layer overlying said first non-magnetic layer, said free magnetic layer having an upper side and a lower side; a second non-magnetic layer overlying said free magnetic layer; a second pinned magnetic layer overlying said second non-magnetic layer; a second antiferromagnetic layer overlying said second pinned magnetic layer, said first and second antiferromagnetic layers serving to fix directions of magnetization of said first and said second pinned magnetic layers by exchange anisotropic magnetic fields; and a bias layer which aligns a direction of magnetization of said free magnetic layer to a direction that intersects said directions of said first and said second pinned magnetic layers, said method comprising: forming at least one of said first and said second antiferromagnetic layers, at least one of said first and said second pinned magnetic layers, said seed layer, and at least one of said upper and said lower sides of said free magnetic layer, by the method of claim 6.
109. A method of producing a magnetoresistive sensor comprising a seed layer; a first antiferromagnetic layer overlying said seed layer; a first pinned magnetic layer overlying said first antiferromagnetic layer; a first non-magnetic layer overlying said first pinned magnetic layer; a free magnetic layer overlying said first non-magnetic layer, said free magnetic layer having an upper side and a lower side; a second non-magnetic layer overlying said free magnetic layer; a second pinned magnetic layer overlying said second non-magnetic layer; a second antiferromagnetic layer overlying said second pinned magnetic layer, said first and second antiferromagnetic layers serving to fix directions of magnetization of said first and said second pinned magnetic layers by exchange anisotropic magnetic fields; and a bias layer which aligns a direction of magnetization of said free magnetic layer to a direction that intersects said directions of said first and said second pinned magnetic layers, said method comprising: forming at least one of said first and said second antiferromagnetic layers, at least one of said first and said second pinned magnetic layers, said seed layer, and at least one of said upper and said lower sides of said free magnetic layer, by the method of claim 9.
110. A method of producing a magnetoresistive sensor comprising a seed layer; a first antiferromagnetic layer overlying said seed layer; a first pinned magnetic layer overlying said first antiferromagnetic layer; a first non-magnetic layer overlying said first pinned magnetic layer; a free magnetic layer overlying said first non-magnetic layer, said free magnetic layer having an upper side and a lower side; a second non-magnetic layer overlying said free magnetic layer; a second pinned magnetic layer overlying said second non-magnetic layer; a second antiferromagnetic layer overlying said second pinned magnetic layer, said first and second antiferromagnetic layers serving to fix directions of magnetization of said first and second pinned magnetic layers by exchange anisotropic magnetic fields; and a bias layer which aligns a direction of magnetization of said free magnetic layer to a direction that intersects said directions of said first and second pinned magnetic layers, said method comprising: forming at least one of said first and said second antiferromagnetic layers, at least one of said first and said second pinned magnetic layers, said seed layer, and at least one of said upper and said lower sides of said free magnetic layer, by the method of claim 28.
111. A method of producing a magnetoresistive sensor comprising a seed layer; a first antiferromagnetic layer overlying said seed layer; a first pinned magnetic layer overlying said first antiferromagnetic layer; a first non-magnetic layer overlying said first pinned magnetic layer; a free magnetic layer overlying said first non-magnetic layer, said free magnetic layer having an upper side and a lower side; a second non-magnetic layer overlying said free magnetic layer; a second pinned magnetic layer overlying said second non-magnetic layer; a second antiferromagnetic layer overlying said second pinned magnetic layer, said first and second antiferromagnetic layers serving to fix directions of magnetization of said first and said second pinned magnetic layers by exchange anisotropic magnetic fields; and a bias layer which aligns a direction of magnetization of said free magnetic layer to a direction that intersects said directions of said first and said second pinned magnetic layers, said method comprising: forming at least one of said first and said second antiferromagnetic layers, at least one of said first and said second pinned magnetic layers, said seed layer, and at least one of said upper and said lower sides of said free magnetic layer, by the method of claim 29.
112. A method of producing a magnetoresistive sensor comprising a magnetoresistive layer having an upper side and a lower side and a soft magnetic layer, said magnetoresistive layer and said soft magnetic layer being superposed through the intermediacy of a non-magnetic layer, an antiferromagnetic layer on said upper side or said lower side of said magnetoresistive layer, said antiferromagnetic layer comprising a plurality of portions spaced apart in a track width direction, and a seed layer contacting said antiferromagnetic layer said method comprising forming said antiferromagnetic layer, said magnetoresistive layer, and said seed layer by the method of in claim 1.
113. A method of producing a magnetoresistive sensor comprising a magnetoresistive layer having an upper side and a lower side and a soft magnetic layer, said magnetoresistive layer and said soft magnetic layer being superposed through the intermediacy of a non-magnetic layer, an antiferromagnetic layer on said upper side or said lower side of said magnetoresistive layer, said antiferromagnetic layer comprising a plurality of portions spaced apart in a track width direction, and a seed layer contacting said antiferromagnetic layer, said method comprising forming said antiferromagnetic layer, said magnetoresistive layer, and said seed layer by the method of claim 2.
114. A method of producing a magnetoresistive sensor comprising a magnetoresistive layer having an upper side and a lower side and a soft magnetic layer, said magnetoresistive layer and said soft magnetic layer being which are superposed through the intermediacy of a non-magnetic layer, an antiferromagnetic layer on said upper side or said lower side of said magnetoresistive layer, said antiferromagnetic layer comprising a plurality of portions spaced apart in a track width direction, and a seed layer contacting said antiferromagnetic layer, said method comprising forming said antiferromagnetic layer, said magnetoresistive layer and said seed layer by the method of claim 8.
115. A method of producing a magnetoresistive sensor comprising a magnetoresistive layer having an upper side and a lower side and a soft magnetic layer, said magnetoresistive layer and said soft magnetic layer being superposed through the intermediacy of a non-magnetic layer, an antiferromagnetic layer on said upper side or said lower side of said magnetoresistive layer, said antiferromagnetic layer comprising a plurality of portions spaced apart in a track width direction, and a seed layer contacting said antiferromagnetic layer said method comprising forming said antiferromagnetic layer, said magnetoresistive layer and said seed layer by the method of claim 9.
116. A method of producing a magnetoresistive sensor comprising a magnetoresistive layer having an upper side and a lower side and a soft magnetic layer, said magnetoresistive layer and said soft magnetic layer being superposed through the intermediacy of a non-magnetic layer, an antiferromagnetic layer on said upper side or said lower side of said magnetoresistive layer, said antiferromagnetic layer comprising a plurality of portions spaced apart in a track width direction, and a seed layer contacting said antiferromagnetic layer, said method comprising forming said antiferromagnetic layer, magnetoresistive layer and said seed layer by the method of claim 28.
117. A method of producing a magnetoresistive sensor comprising a magnetoresistive layer having an upper side and a lower side and a soft magnetic layer, said magnetoresistive layer and said soft magnetic layer being superposed through the intermediacy of a non-magnetic layer, an antiferromagnetic layer on said upper side or said lower side of said magnetoresistive layer, said antiferromagnetic layer comprising a plurality of antiferromagnetic layer, portions spaced apart in a track width direction, and a seed layer contacting said antiferromagnetic layer, said method comprising forming said antiferromagnetic layer, said magnetoresistive layer and said seed layer by the method of claim 29.
BACKGROUND
[0001] The present invention relates to methods of producing an exchange coupling film having an antiferromagnetic layer and a ferromagnetic layer, wherein the direction of magnetization of the ferromagnetic layer is fixed by an exchange coupling magnetic field produced at the interface between the antiferromagnetic layer and the ferromagnetic layer. More particularly, the present invention relates to methods of producing an exchange coupling film that provides a large ratio of resistance variation, to methods of producing a magnetoresistive sensor (spin-valve-type thin-film device, AMR device), and to methods of producing a thin-film magnetic head using the magnetoresistive sensor.
Description of the Related Art
[0002] A spin-valve-type thin-film device is a kind of GMR (Giant Magnetoresistive) device which makes use of a giant magnetoresistive effect, which is used for detecting recording magnetic fields from a recording medium such as a hard disk.
[0003] The spin-valve-type thin-film device, relative to other GMR devices, has advantageous features such as simplicity of structure and ability to vary its magnetic resistance even under a weak magnetic field.
[0004] The simplest form of the spin-valve-type thin-film device includes an antiferromagnetic layer, a pinned magnetic layer, a non-magnetic intermediate layer, and a free magnetic layer.
[0005] The antiferromagnetic layer and the pinned magnetic layer are formed in contact with each other. The direction of the pinned magnetic layer is aligned in a single magnetic domain state and fixed by an exchange anisotropic magnetic field produced at the interface between the antiferromagnetic layer and the pinned magnetic layer.
[0006] The magnetization of the free magnetic layer is aligned in a direction which intersects the direction of magnetization of the pinned magnetic layer, by the effect of bias layers that are formed on both sides of the free magnetic layer.
[0007] Alloy films such as Fe—Mn (Iron-Manganese) alloy films, Ni—Mn (Nickel-Manganese) alloy films, and Pt—Mn (Platinum-Manganese) alloy films are generally usable materials for the antiferromagnetic layer. Of these, Pt—Mn alloy films are attracting attention for advantages such as a high blocking temperature, superior corrosion resistance, and so forth.
[0008] In order to comply with future demand for higher recording density, it is important to achieve greater exchange coupling magnetic fields and greater ratios of resistance variation.
[0009] However, it has been impossible to obtain a large ratio of resistance variation with conventional structures of magnetoresistive sensors, which are composed of an antiferromagnetic layer, a pinned magnetic layer, a non-magnetic intermediate layer and a free magnetic layer.
[0010] It has been found that the ratio of resistance variation is dependent on exchange coupling magnetic field. The resistance variation ratio decreases unless a large exchange coupling magnetic field is obtained. The resistance variation ratio is also dependent on the crystalline orientations of the layers. It has been heretofore impossible to use conventional structures to obtain a magnetoresistive sensor which possesses both appropriate crystalline orientations and a large exchange magnetic field, and which therefore exhibits a large resistance variation ratio.
SUMMARY
[0011] Accordingly, an object of the present invention is to provide methods of producing an exchange coupling film in which a seed layer is provided on the side of an antiferromagnetic layer opposite to the interface between the antiferromagnetic layer and the ferromagnetic layer, so as to optimize the crystalline orientations of these layers. Thus, a greater resistance variation ratio than obtained with conventional devices is achieved. Additional objects are to provide methods of producing a magnetoresistive sensor using the exchange coupling film, and methods of producing a thin-film magnetic head using the magnetoresistive sensor. In accord with the present invention, the above-described problems are overcome.
[0012] In accord with the present invention, there is provided a method of producing an exchange coupling film comprising an antiferromagnetic layer, a ferromagnetic layer contacting the antiferromagnetic layer at an interface therebetween, and a seed layer comprising a (111) plane of face-centered cubic crystal, which seed layer contacts the antiferromagnetic layer at an interface therebetween on a side opposite the ferromagnetic layer. The method comprises forming the seed layer such that the (111) plane of face-centered cubic crystal is preferentially oriented in a direction parallel to the direction of the interface between the seed layer and the antiferromagnetic layer, while creating a non-aligned state at at least a part of the interface between the antiferromagnetic layer and the seed layer. The method further comprises effecting a heat-treatment after formation of the layers, so as to develop an exchange coupling magnetic field at the interface between the antiferromagnetic layer and the ferromagnetic layer.
[0013] As stated above, in accordance with the present invention, a seed layer contacts the antiferromagnetic layer on a side thereof opposite the interface between the antiferromagnetic layer and the ferromagnetic layer. The layer is constituted mainly by a face-centered cubic crystalline structure in which, prior to heat treatment, the (111) plane is preferentially oriented in a direction parallel to the interface. This allows the (111) plane of the antiferromagnetic layer in contact with the seed layer, and the (111) plane of the ferromagnetic layer which, together with the seed layer, sandwhiches the antiferromagnetic layer, to be preferentially oriented in a direction parallel to the interface.
[0014] It is possible to enhance the resistance variation ratio of a magnetoresistive sensor by using an exchange coupling film in which the (111) planes of the antiferromagnetic layer and the ferromagnetic layer are preferentially oriented, as described above.
[0015] The enhancement of the resistance variation ratio requires that a large exchange-coupling magnetic field be developed at the interface between the antiferromagnetic layer and the ferromagnetic layer. In accordance with the present invention, at least a part of the interface between the layers is executed such that a non-aligned state is created at at least a part of the interface between the antiferromagnetic layer and the seed layer. Such a non-aligned state of the interface between the seed layer and the antiferromagnetic layer permits the antiferromagnetic layer to be adequately transformed from a disordered lattice into an ordered lattice upon heat-treatment. As a result, a large exchange coupling magnetic field and, therefore, an enhanced resistance variation ratio can be achieved.
[0016] The present invention also provides a method of producing an exchange coupling film comprising an antiferromagnetic layer, a ferromagnetic layer contacting the antiferromagnetic layer at an interface therebetween, and a seed layer comprising a (111) plane of face-centered cubic crystal, which seed layer contacts the antiferromagnetic layer at an interface therebetween on a side opposite the ferromagnetic layer, the method comprising forming the seed layer such that the (111) plane of face-centered cubic crystal is preferentially oriented in a direction parallel to the direction of the interface between the seed layer and the antiferromagnetic layer, while creating a difference in lattice constant between the antiferromagnetic layer and the seed layer at at least a part of the interface therebetween. The method further comprises effecting a heat-treatment after formation of the layers, so that an exchange coupling magnetic field is developed at the interface between the antiferromagnetic layer and the ferromagnetic layer.
[0017] In accordance with the present invention, the antiferromagnetic layer and the ferromagnetic layer have different lattice constants at at least a part of the interface between the antiferromagnetic layer and the seed layer. Preferably, a non-aligned state is created at at least a part of the interface between the antiferromagnetic layer and the seed layer. These features make it possible to obtain a large exchange coupling magnetic field and, hence, a large resistance variation ratio.
[0018] In accordance with the present invention, the antiferromagnetic layer preferably comprises an element X and Mn, wherein the element X is selected from the group consisting of Pt, Pd, Ir, Rh, Ru, Os, and combinations thereof.
[0019] Alternatively, the antiferromagnetic layer may comprise an element X, an element X′ and Mn, wherein the element X is selected from the group consisting of Pt, Pd, Ir, Rh, Ru, Os, and combinations thereof, while the element X′ is selected from the group consisting of Ne, Ar, Kr, Xe, Be, B, C, N, Mg, Al, Si, P, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, Cd, Sn, Hf, Ta, W, Re, Au, Pb, a rare earth element, and combinations thereof.
[0020] The present invention also provides methods of producing an exchange coupling film comprising an antiferromagnetic layer, a ferromagnetic layer contacting the antiferromagnetic layer at an interface therebetween, and a seed layer comprising a (111) plane of face-centered cubic crystal, which seed layer contacts the antiferromagnetic layer at an interface therebetween on a side opposite the ferromagnetic layer, the method comprising: forming the seed layer such that the (111) plane of face-centered cubic crystal is preferentially oriented in a direction parallel to the interface between the seed layer and the antiferromagnetic layer; depositing on the seed layer an antiferromagnetic layer comprising an element X and Mn, wherein X is selected from the group consisting of Pt, Pd, Ir, Rh, Ru, Os, and combinations thereof; elevating a sputtering gas pressure during the depositing so that a composition ratio (at %) of the element X in the antiferromagnetic layer progressively decreases as distance from the seed layer increases; decreasing the sputtering gas pressure during the depositing so that the composition ratio (at %) of the element X of the antiferromagnetic layer progressively increases as distance from the seed layer further increases; and effecting a heat-treatment after formation of the layers, so as to develop an exchange coupling magnetic field at the interface between the antiferromagnetic layer and the ferromagnetic layer.
[0021] The present invention also provides a method of producing an exchange coupling film comprising an antiferromagnetic layer, a ferromagnetic layer contacting the antiferromagnetic layer at an interface therebetween, and a seed layer comprising a (111) plane of face-centered cubic crystal, which seed layer contacts the antiferromagnetic layer at an interface therebetween on a side opposite to ferromagnetic layer, the method comprising: forming the seed layer such that the (111) plane of face-centered cubic crystal is preferentially oriented in a direction parallel to the interface between the seed layer and the antiferromagnetic layer; depositing on the seed layer an antiferromagnetic layer comprising an element X, an element X′ and Mn, wherein X is selected from the group consisting of Pt, Pd, Ir, Rh, Ru, Os, and combinations thereof, and X′ is selected from the group consisting of Ne, Ar, Kr, Xe, Be, B, C, N, Mg, Al, Si, P, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, Cd, Sn, Hf, Ta, W, Re, Au, Pb, a rare earth element, and combinations thereof; elevating a sputtering gas pressure during the depositing so that a composition ratio (at %) of the elements X+X′ of the antiferromagnetic layer progressively decreases as distance from the seed layer increases; decreasing the sputtering gas pressure during the depositing so that the composition ratio (at %) of the elements X+X′ of the antiferromagnetic layer progressively increases as distance from the seed layer further increases; and effecting a heat-treatment after formation of the layers, so as to develop an exchange coupling magnetic field at the interface between the antiferromagnetic layer and the ferromagnetic layer.
[0022] According to this method of the present invention, a portion of a composition prone to order transformation is formed near the middle of the antiferromagnetic layer. The antiferromagnetic layer is formed such that the composition of the antiferromagnetic layer at the interface between the seed layer and the antiferromagnetic layer is not constrained by factors such as the crystalline structure of the seed layer.
[0023] In these methods of the present invention, the composition ratio of the element X or the composition ratio of the elements X+X′ of the antiferromagnetic layer to the total composition ratio (100 at %) of all the elements constituting the antiferromagnetic layer is not less than 53 at % and not more than 65 at %, preferably not less than 55 at % and not more than 60 at %, in a region near the interface between the antiferromagnetic layer and the ferromagnetic layer, and in a region near the interface between the antiferromagnetic layer and the seed layer.
[0024] In these methods of the present invention, it is also preferred that the composition ratio of the element X or the composition ratio of the elements X+X′ is not less than 44 at % and not more than 57 at %, more preferably not less than 46 at % and not more than 55 at %, in a region near the thicknesswise central portion of the antiferromagnetic layer.
[0025] Preferably, the antiferromagnetic layer is formed to have a thickness of 76 Å or greater.
[0026] The present invention also provides a method of producing an exchange coupling film comprising an antiferromagnetic layer, a ferromagnetic layer contacting the antiferromagnetic layer at an interface therebetween, and a seed layer comprising a (111) plane of face-centered cubic crystal, which seed layer contacts the antiferromagnetic layer at an interface therebetween on a side opposite to the ferromagnetic layer, the antiferromagnetic layer comprising a first antiferromagnetic layer, a second antiferromagnetic layer, and a third antiferromagnetic layer, the method comprising: forming the seed layer such that the (111) plane of face-centered cubic crystal is preferentially oriented in a direction parallel to the interface between the seed layer and the antiferromagnetic layer; forming the antiferromagnetic layer such that the third antiferromagnetic layer is adjacent to the seed layer, the first antiferromagnetic layer is adjacent to the ferromagnetic layer, and the second antiferromagnetic layer is between the first and third antiferromagnetic layers, wherein each of the first, the second, and the third antiferromagnetic layers comprises an element X and Mn, wherein X is selected from the group consisting of Pt, Pd, Ir, Rh, Ru, Os, and combinations thereof, such that the second antiferromagnetic layer has a smaller composition ratio of the element X than the first and the second antiferromagnetic layers; and effecting a heat-treatment after formation of the layers, such that an exchange coupling magnetic field is developed at the interface between the antiferromagnetic layer and the ferromagnetic layer.
[0027] In this method of the present invention, the first, second and third antiferromagnetic layers may be formed from antiferromagnetic materials comprising an element X, an element X′ and Mn, wherein the element X′ is selected from the group consisting of Ne, Ar, Kr, Xe, Be, B, C, N, Mg, Al, Si, P, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, Cd, Sn, Hf, Ta, W, Re, Au, Pb, a rare earth element, and combinations thereof.
[0028] In this method of the present invention, the antiferromagnetic layer is composed of a triple-layer laminate. During deposition of the third antiferromagnetic layer, the composition ratio of the element X in the third antiferromagnetic layer is set to be greater than that of the second antiferromagnetic layer so that, at the interface between the third antiferromagnetic layer and the seed layer, the restraint force produced by the crystalline structure of the seed layer is weakened. As a result, a non-aligned state or a different lattice constant is obtained, thereby facilitating transformation of the antiferromagnetic layer to an ordered lattice upon heat-treatment without influence from the crystalline structure of the seed layer. As a result, a greater exchange coupling magnetic field is obtained than heretofore.
[0029] Setting the composition ratio of the element X in the second antiferromagnetic layer to a value smaller than in the first and third antiferromagnetic layers facilitates transformation of the second antiferromagnetic layer upon heat-treatment. This in turn promotes transformation of the whole antiferromagnetic layer through a diffusion of the composition, whereby a large exchange coupling magnetic field is obtained.
[0030] In accordance with the present invention, the antiferromagnetic layer and the seed layer may have different lattice constants at at least a part of the interface therebetween. Preferably, in accord with the present invention, a non-aligned state is created at at least a part of the interface between the antiferromagnetic layer and the seed layer.
[0031] When the above-mentioned X—Mn—X′ alloy is used as the material of the antiferromagnetic layer, it is preferred that the element X′ is an element which either invades the interstices of a space lattice composed of the element X and Mn, or substitutes for a portion of the lattice points of a crystalline lattice constituted by Mn and the element X.
[0032] In accordance with the present invention, the composition ratio of the element X or the composition ratio of the elements X+X′ of each of the first and third antiferromagnetic layers is preferably not less than 53 at % and not more than 65 at %, more preferably not less than 55 at % and not more than 60 at %.
[0033] In accordance with the present invention, it is also preferred that the composition ratio of the element X or the composition ratio of the elements X+X′ of the second antiferromagnetic layer is not less than 44 at % and not more than 57 at %, more preferably not less than 46 at % but not more than 55 at %.
[0034] In accordance with the present invention, it is preferred that each of the first and third antiferromagnetic layers has a thickness not smaller than 3 Å and not greater than 30 Å.
[0035] In accordance with the present invention, it is also preferred that the second antiferromagnetic layer has a thickness of 70 Å or greater.
[0036] In accordance with the present invention, it is preferred that the antiferromagnetic layer and the ferromagnetic layer have different lattice constants at at least a part of the interface therebetween. In addition, it is preferred that a non-aligned state is created at at least a part of the above-mentioned interface. With these features, an appropriate ordered transformation of the entire antiferromagnetic layer is facilitated.
[0037] In accordance with the present invention, it is preferred that the seed layer is formed of a Ni—Fe alloy or a Ni—Fe—Y alloy, wherein Y is selected from the group consisting of Cr, Rh, Ta, Hf, Nb, Zr, Ti, and combinations thereof.
[0038] It is also preferred that the seed layer is non-magnetic. The non-magnetic nature of the seed layer serves to enhance the specific resistance of the seed layer, so that shunting of a sense current to the seed layer is suppressed. As a result, greater resistance variation ratio in the exchange coupling film obtained after heat-treatment is obtained.
[0039] In accordance with the present invention, it is preferred that the exchange coupling film is formed by sequentially depositing a seed layer, an antiferromagnetic layer, and a ferromagnetic layer on an underlying layer, wherein the underlying layer comprises an element selected from the group consisting of Ta, Hf, Nb, Zr, Ti, Mo, W, and combinations thereof.
[0040] This facilitates formation of a seed layer having a crystalline structure constituted mainly by face-centered cubic crystals with the (111) plane preferentially oriented in a direction parallel to the above-mentioned interface The methods of producing an exchange coupling film described hereinabove can be used for the production of a variety of types of magnetoresistive sensors.
[0041] In accordance with the present invention, there is provided a method of producing a magnetoresistive sensor comprising an antiferromagnetic layer, a seed layer contacting the antiferromagnetic layer at an interface therebetween, a pinned magnetic layer contacting the antiferromagnetic layer at an interface therebetween which has a direction of magnetization fixed by an exchange anisotropic magnetic field with the antiferromagnetic layer, a non-magnetic intermediate layer between the pinned magnetic layer and a free magnetic layer, and a bias layer which aligns a direction of magnetization of the free magnetic layer in a direction that intersects the direction of magnetization of the pinned magnetic layer, the method comprising forming the antiferromagnetic layer, the pinned magnetic layer, and the seed layer by one of the methods described hereinabove.
[0042] In accordance with the present invention, there is provided a method of producing a magnetoresistive sensor comprising an antiferromagnetic layer, a seed layer contacting the antiferromagnetic layer at an interface therebetween, a pinned magnetic layer contacting the antiferromagnetic layer at an interface therebetween which has a direction of magnetization fixed by an exchange anisotropic magnetic field with the antiferromagnetic layer, a non-magnetic intermediate layer between the pinned magnetic layer and a free magnetic layer having an upper side and a lower side, and an antiferromagnetic exchange bias layer formed on either the upper side or the lower side of the free magnetic layer, the antiferromagnetic exchange bias layer comprising at least one gap in the track width direction, the method comprising: forming the exchange bias layer, the free magnetic layer and the seed layer by one of the methods described hereinabove.
[0043] The present invention also provides a method of producing a magnetoresistive sensor comprising a seed layer; a first antiferromagnetic layer overlying the seed layer; a first pinned magnetic layer overlying the first antiferromagnetic layer; a first non-magnetic layer overlying the first pinned magnetic layer; a free magnetic layer overlying the first non-magnetic layer, the free magnetic layer having an upper side and a lower side; a second non-magnetic layer overlying the free magnetic layer; a second pinned magnetic layer overlying the second non-magnetic layer; a second antiferromagnetic layer overlying the second pinned magnetic layer, the first and second antiferromagnetic layers serving to fix directions of magnetization of the first and the second pinned magnetic layers by exchange anisotropic magnetic fields; and a bias layer which aligns a direction of magnetization of the free magnetic layer to a direction that intersects the directions of the first and the second pinned magnetic layers, the method comprising: forming at least one of the first and the second antiferromagnetic layers, at least one of the first and the second pinned magnetic layers, the seed layer, and at least one of the lower side and the upper side of the free magnetic layer, by one of the methods described hereinabove.
[0044] The present invention also provides a method of producing a magnetoresistive sensor comprising a magnetoresistive layer having an upper side and a lower side and a soft magnetic layer, the magnetoresistive layer and the soft magnetic layer being superposed through the intermediacy of a non-magnetic layer, an antiferromagnetic layer on the upper side or the lower side of the magnetoresistive layer, the antiferromagnetic layer comprising at least one gap in the track width direction, and a seed layer contacting the antiferromagnetic layer, the method comprising the forming the antiferromagnetic layer, the magnetoresistive layer and the seed layer by one of the methods described hereinabove.
[0045] A method for producing a thin-film magnetic head in accord with the present invention comprises forming a shield layer across the gap layer, on each of the upper side and the lower side of a magnetoresistive sensor produced by one of the methods described hereinabove.
BRIEF DESCRIPTION OF THE DRAWINGS
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DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS
[0067]
[0068] This single-spin valve type magnetoresistive sensor can be provided on a trailing side end of a floating slider of a hard disk device, and can be used to detect the recording magnetic fields of the hard disk. A recording medium such as the hard disk moves in the Z direction, while the magnetic field leaks from the hard disk in the Y direction.
[0069] Referring to
[0070] As shown in
[0071] In accordance with the present invention, each of free magnetic layer
[0072] In the structure shown in
[0073] The non-magnetic intermediate layer
[0074] A method of producing a magnetoresistive sensor in accord with the present invention, will be described, followed by a description of the features of the magnetoresistive sensor produced.
[0075]
[0076] Initially, underlying layer
[0077] By way of example, a Ni—Fe alloy film
[0078] The Ni—Fe alloy film
[0079] Non-magnetic intermediate layer
[0080] Pinned magnetic layer
[0081] By way of example, pinned magnetic layer
[0082] The Co film
[0083] Antiferromagnetic layer
[0084] In accordance with the present invention, each of the first antiferromagnetic layer
[0085] X-
[0086] In accordance with the present invention, each of the first antiferromagnetic layer
[0087] Preferably, the element X′ is an element which invades the interstices of the space lattice constituted by the element X and Mn, or an element which substitutes for a portion of the lattice points of a crystalline lattice formed by the element X and Mn. The term “solid solution” as used herein means a solid in which components are uniformly mixed over a wide region.
[0088] The formation of an interstitial solid solution or a substitutional solid solution enables the lattice constant of the X—Mn—X′ alloy to be greater than the lattice constant of the aforementioned X—Mn alloy, which results in a larger difference in lattice constant relative to the lattice constant of the pinned magnetic layer
[0089] When the element X′ is a gaseous element, it is difficult to incorporate a large amount of it in the film. However, a trace amount of a rare gas element X′ drastically increases the exchange coupling magnetic field generated upon heat-treatment.
[0090] In accordance with the present invention, the composition ratio of the element X′ preferably ranges from 0.2 at % to 10 at %, more preferably from 0.5 at % to 5 at %. In accordance with the present invention, it is possible to use Pt as the element X and, hence, to use a Pt—Mn—X′ alloy.
[0091] The element X and elements X+X′ which form the first antiferromagnetic layer
[0092] In the laminate structure after deposition (prior to heat-treatment) shown in
[0093] After the second antiferromagnetic layer
[0094] In order to reduce the influence of the restraint force produced by the crystalline structure of pinned magnetic layer
[0095] A large composition ratio of the element X or elements X+X′ reduces the tendency of the composition to form an ordered lattice upon heat-treatment, but increases the difference in lattice constants relative to the pinned magnetic layer. Increased differences in lattice constants reduces the influence of the restraint force produced by the crystalline structure of pinned magnetic layer
[0096] In accordance with the present invention, it is preferred that a non-aligned state is created at part of the interface between the first antiferromagnetic layer
[0097] As noted above, in a bulk type Pt—Mn alloy, a CuAu—I type face-centered cubic ordered lattice is easiest to obtain—and, therefore, antiferromagnetic properties are easiest to achieve—when the at % ratio between Pt and Mn is 50:50. Increasing the Pt content beyond 50 at % weakens the antiferromagnetic properties on the one hand, but increases the lattice constant of the Pt—Mn alloy on the other, thereby facilitating creation of non-aligned state at the interface between the pinned magnetic layer
[0098] Preferably, the composition ratio of the element X or the elements X+X′ of the first antiferromagnetic layer
[0099] It is to be understood that there are preferred thicknesses for the first antiferromagnetic layer
[0100] In accordance with the present invention, the thickness of the first antiferromagnetic layer
[0101] A second antiferromagnetic layer
[0102] Preferably, the composition ratio of the element X or the elements X+X′ in the second antiferromagnetic layer
[0103] It is also preferred that the composition ratio of the element X or the elements X+X′ in the second antiferromagnetic layer
[0104] It is to be noted that there are preferred thicknesses of the second antiferromagnetic layer
[0105] In accordance with the present invention, it is preferred that the second antiferromagnetic layer
[0106] In accordance with the present invention, it is preferred that the first antiferromagnetic layer
[0107] In particular, when the first antiferromagnetic layer
[0108] In accordance with the present invention, the deposition of the first antiferromagnetic layer
[0109] Thus, in accordance with the present invention, it is preferred that the antiferromagnetic layer
[0110] In accordance with the present invention, as noted above, it is preferred that a non-aligned state is created at at least a part of the interface between the first antiferromagnetic layer
[0111] Alternatively, different crystal orientations are created at at least a part of the first antiferromagnetic layer
[0112] For instance, when the (111) plane of pinned magnetic layer
[0113] Alternatively, when the (111) plane of the first antiferromagnetic layer
[0114] Alternatively, the degrees of orientation of the (111) faces of first antiferromagnetic layer