TUNNEL-TYPE MAGNETIC DETECTING ELEMENT AND METHOD OF MANUFACTURING THE SAME

Abstract

A tunnel-type magnetic detecting element is provided. The tunnel-type magnetic detecting element includes a first ferromagnetic layer; an insulating barrier layer; and a second ferromagnetic layer. The first ferromagnetic layer, the second ferromagnetic layer, or both have a Heusler alloy layer contacting the insulating barrier layer. Equivalent planes represented by {110} surfaces, are preferentially oriented parallel to a film surface in the Heusler alloy layer. The insulating barrier layer is formed of MgO and the equivalent crystal planes represented by the {100} surfaces or the equivalent crystal planes represented by the {110} surfaces are oriented parallel to the film surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing one embodiment of a reproducing head having a tunnel-type magnetoresistance effect element cut from a direction parallel to a recording medium.

FIG. 2 is a cross-sectional view showing one embodiment of a recording head having a tunnel-type magnetic detecting element cut from a direction parallel to a surface opposite to a recording medium.

FIG. 3 shows a crystal structure of a Hesuler alloy represented by X₂YZ or XYZ.

FIG. 4 shows a crystal structure of MgO.

FIG. 5A shows the atomic arrangement of (001) surfaces of Co₂MnZ.

FIG. 5B shows the atomic arrangement of (110) surfaces of Co₂MnZ.

FIG. 6A shows the atomic arrangement of (001) surfaces of MgO.

FIG. 6B shows the atomic arrangement of (110) surfaces of MgO.

FIG. 6C shows the atomic arrangement of (111) surfaces of MgO.

FIG. 7 shows the atomic arrangement when (001) surfaces of MgO shown in FIG. 6A are overlapped with (110) surfaces of Co₂MnZ shown in FIG. 5B as viewed immediately from an upper side.

FIG. 8 shows the atomic arrangement when (110) surfaces of MgO shown in FIG. 6B are overlapped with (110) surfaces of Co₂MnZ shown in FIG. 5B as viewed immediately from an upper side.

FIG. 9 shows the atomic arrangement when (111) surfaces of MgO shown in FIG. 5C are overlapped with (110) surfaces of Co₂MnZ shown in FIG. 5A as viewed immediately from an upper side.

FIG. 10A shows a transmitted electron beam diffraction pattern of an insulating barrier layer in a first tunnel-type magnetic detecting element in which {100} surfaces of an insulating barrier layer formed of MgO and

FIG. 10B shows a transmitted electron beam diffraction pattern of the insulating barrier layer in a second tunnel-type magnetic detecting element in which {100} surfaces of the insulating barrier layer formed of Mgo are preferentially oriented parallel to the film surface.

FIG. 11 is a graph showing magnetoresistance variation rates (^ΔR/R) of a first tunnel-type magnetic detecting element and a second-type magnetic detecting element.

Claims

1. A tunnel-type magnetic detecting element comprising: a first ferromagnetic layer;an insulating barrier layer; anda second ferromagnetic layer,wherein the first ferromagnetic layer, the second ferromagnetic layer, or both have a Heusler alloy layer contacting the insulating barrier layer, and equivalent planes represented by {110} surfaces, are preferentially oriented parallel to a film surface in the Heusler alloy layer, andwherein the insulating barrier layer is formed of MgO and the equivalent crystal planes represented by the {100} surfaces or the equivalent crystal planes represented by the {110} surfaces are oriented parallel to the film surface.

2. The tunnel-type magnetic detecting element according to claim 1, wherein the equivalent crystal planes represented by the {100} surfaces are preferentially oriented parallel to the film surface in the insulating barrier layer.

3. The tunnel-type magnetic detecting element according to claim 1, wherein the first ferromagnetic layer is a fixed magnetic layer, which is fixed in magnetization and the second ferromagnetic layer is a free magnetic layer, which is variable in magnetization by an external magnetic field, andwherein the first ferromagnetic layer comprises the Heusler alloy layer.

4. The tunnel-type magnetic detecting element according to claim 1, wherein the Heusler alloy layer is formed of a metal compound having a Heusler-type crystal structure.

5. The tunnel-type magnetic detecting element according to claim 4, wherein the Heusler alloy layer is formed of the metal compound represented by the composition formula of X2YZ.

6. A method of manufacturing a tunnel-type magnetic detecting element, which includes a first ferromagnetic layer, an insulating barrier layer, and a second ferromagnetic layer sequentially laminated from the bottom, the method comprising: (a) forming a Heusler alloy layer, which comprises crystal planes represented by {100} surfaces that are preferentially oriented parallel to a film surface, as at least a surface layer of the first ferromagnetic layer; and(b) sputter-forming the insulating barrier layer formed of MgO on the Heusler alloy layer by using an MgO target.

7. A method of manufacturing a tunnel-type magnetic detecting element, which includes a first ferromagnetic layer, an insulating barrier layer, and a second ferromagnetic layer sequentially laminated from the bottom, the method comprising: (c) sputter-forming the insulating barrier layer made of MgO on the first ferromagnetic layer by using an MgO target; and(d) forming a Heusler alloy layer that includes equivalent crystal planes represented by {110} surfaces that are oriented parallel to a film surface, as at least a part of the second ferromagnetic layer.

8. The method of manufacturing a tunnel-type magnetic detecting element according to claim 7, the method further comprising: (e) forming the Heusler alloy layer, as at least a surface layer of the first ferromagnetic layer, prior to (c).

9. The method of manufacturing a tunnel-type magnetic detecting element according to claim 6, wherein the insulating barrier layer formed of Mgo is formed by oxidizing an Mg layer after forming the Mg layer by the Mg target, instead of (b) or (c).

10. The method of manufacturing a tunnel-type magnetic detecting element according to claim 9, wherein oxidizing the Mg layer is performed once more after formation of the Mg layer.

11. The method of manufacturing a tunnel-type magnetic detecting element according to claim 6, wherein the Heusler alloy layer is formed of a metal compound having a Heusler-type crystal structure.

12. The method of manufacturing a tunnel-type magnetic detecting element according to claim 11, wherein the Heusler alloy layer is formed of the metal compound represented by the composition formula of X2YZ.

13. The tunnel-type magnetic detecting element according to claim 4, wherein the Heusler alloy layer is formed of the metal compound represented by the composition formula of X2YZ and XYZ.

14. The tunnel-type magnetic detecting element according to claim 13, wherein the X represents one or more kinds of elements out of Cu, Co, Ni, Rh, Pt, Au, Pd, Ir, Ru, Ag, Zn, Cd, or Fe, the Y represents one or more kinds of elements out of Mn, Fe, Ti, V, Zr, Nb, Hf, Ta, Cr, Co, or Ni, and the Z represents one or more kinds of elements out of Al, Sn, In, Sb, Ga, Si, Ge, Pb, or Zn.

15. The tunnel-type magnetic detecting element according to claim 5, wherein the X represents one or more kinds of elements out of Cu, Co, Ni, Rh, Pt, Au, Pd, Ir, Ru, Ag, Zn, Cd, or Fe, the Y represents one or more kinds of elements out of Mn, Fe, Ti, V, Zr, Nb, Hf, Ta, Cr, Co, or Ni, and the Z represents one or more kinds of elements out of Al, Sn, In, Sb, Ga, Si, Ge, Pb, or Zn.

16. The method of manufacturing a tunnel-type magnetic detecting element according to claim 6, wherein one ferromagnetic layer is a fixed magnetic layer and the other ferromagnetic layer is a free magnetic layer, which is variably magnetized by an external magnetic field.

17. The method of manufacturing a tunnel-type magnetic detecting element according to claim 7, wherein one ferromagnetic layer is a fixed magnetic layer and the other ferromagnetic layer is a free magnetic layer, which is variably magnetized by an external magnetic field.

18. The method of manufacturing a tunnel-type magnetic detecting element according to claim 11, wherein the Heusler alloy layer is formed of the metal compound represented by the composition formula of X2YZ or XYZ.

19. The method of manufacturing a tunnel-type magnetic detecting element according to claim 12, wherein the X represents X represents one or more kinds of elements out of Cu, Co, Ni, Rh, Pt, Au, Pd, Ir, Ru, Ag, Zn, Cd, or Fe, the Y represents one or more kinds of elements out of Mn, Fe, Ti, V, Zr, Nb, Hf, Ta, Cr, Co, or Ni, and the Z represents one or more kinds of elements out of Al, Sn, In, Sb, Ga, Si, Ge, Pb, or Zn.

20. The method of manufacturing a tunnel-type magnetic detecting element according to claim 18, wherein the X represents X represents one or more kinds of elements out of Cu, Co, Ni, Rh, Pt, Au, Pd, Ir, Ru, Ag, Zn, Cd, or Fe, the Y represents one or more kinds of elements out of Mn, Fe, Ti, V, Zr, Nb, Hf, Ta, Cr, Co, or Ni, and the Z represents one or more kinds of elements out of Al, Sn, In, Sb, Ga, Si, Ge, Pb, or Zn.