초록 ▼

An exchange coupling film including an antiferromagnetic layer and a ferromagnetic layer in contact with the antiferromagnetic layer so as to generate an exchange coupling magnetic field is provided. A PtMn alloy is used as the material of the antiferromagnetic layer. Crystal planes of the antifer

An exchange coupling film including an antiferromagnetic layer and a ferromagnetic layer in contact with the antiferromagnetic layer so as to generate an exchange coupling magnetic field is provided. A PtMn alloy is used as the material of the antiferromagnetic layer. Crystal planes of the antiferromagnetic layer and the ferromagnetic layer preferentially aligned parallel to the interface are crystallographically identical and crystallographically identical axes lying in these crystal planes are oriented, at least partly, in different directions between the antiferromagnetic layer and the ferromagnetic layer. Thus, a proper order transformation occurs in the antiferromagnetic layer as a result of heat treatment and an increased exchange coupling magnetic field can be obtained.

대표청구항 ▼

What is claimed is: 1. An exchange coupling film comprising an antiferromagnetic layer and a ferromagnetic layer in contact with the antiferromagnetic layer, in which an exchange coupling magnetic field generated at the interface between the antiferromagnetic layer and the ferromagnetic layer magne

What is claimed is: 1. An exchange coupling film comprising an antiferromagnetic layer and a ferromagnetic layer in contact with the antiferromagnetic layer, in which an exchange coupling magnetic field generated at the interface between the antiferromagnetic layer and the ferromagnetic layer magnetizes the ferromagnetic layer in a particular direction, wherein diffraction spots corresponding to reciprocal lattice points indicative of crystal planes of the antiferromagnetic layer and the ferromagnetic layer appear in transmission electron beam diffraction diagrams of the antiferromagnetic layer and the ferromagnetic layer obtained using an electron beam in a direction parallel to the interface, wherein first imaginary lines in the diffraction diagrams of the antiferromagnetic layer and the ferromagnetic layer, the first imaginary lines each connecting a beam origin and a particular one of the diffraction spots which is given the same label in both the diffraction diagrams of the antiferromagnetic layer and the ferromagnetic layer and which is located in a layer thickness direction when viewed from the beam origin, are coincident with each other, and wherein second imaginary line in the diffraction diagrams of the antiferromagnetic layer and the ferromagnetic layer, the second imaginary lines each connecting the beam origin and a particular one of the diffraction spots which is given the same label in both the diffraction diagrams of the antiferromagnetic layer and the ferromagnetic layer and which is located in a direction other than the layer thickness direction when viewed from the beam origin, are not coincident with each other. 2. An exchange coupling film according to claim 1, wherein the diffraction spots located in the layer thickness direction are assigned to the {111} planes. 3. An exchange coupling film according to claim 1, wherein the antiferromagnetic layer and the ferromagnetic layer are deposited in that order from the bottom, the exchange coupling film further comprising a seed layer provided below the antiferromagnetic layer, the seed layer mainly having a face-centered cubic structure and having the crystallographically identical planes generically described as the {111} planes, one of the {111} planes being preferentially aligned parallel to the interface. 4. An exchange coupling film according to claim 3, wherein the seed layer comprises one of a NiFe alloy and a Ni--Fe--Y alloy, wherein Y is at least one element selected from the group consisting of Cr, Rh, Ta, Hf, Nb, Zr, and Ti. 5. An exchange coupling film according to claim 3, wherein the seed layer is nonmagnetic at room temperature. 6. An exchange coupling film according to claim 3, further comprising an underlayer provided under the seed layer, the underlayer comprising at least one element selected from the group consisting of Ta, Hf, Nb, Zr, Ti, Mo, and W. 7. An exchange coupling film according to claim 3, wherein at least part of the interface between the antiferromagnetic layer and the seed layer is in a lattice-mismatching state. 8. An exchange coupling film according to claim 3, the antiferromagnetic material further comprising X', wherein X' is at least one element 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, and rare earth elements. 9. An exchange coupling film according to claim 8, wherein the antiferromagnetic material is an interstitial solid solution in which X' is inserted to interstices in the lattice formed by X and Mn or a substitutional solid solution in which X' partly displaces the lattice points in the crystal lattice formed by X and Mn. 10. An exchange coupling film according to claim 9, wherein the X or X+X' content in the antiferromagnetic material is in the range of 45 to 60 atomic percent. 11. An exchange coupling film according to claim 1, wherein at least part of the interface between the antiferromagnetic layer and the ferromagnetic layer is in a lattice-mismatching state. 12. A magnetoresistive element comprising: an antiferromagnetic layer; a pinned magnetic layer in contact with the antiferromagnetic layer, the magnetization vector of the pinned magnetic layer being pinned by an exchanged anisotropic magnetic field generated in relation to the antiferromagnetic layer; a free magnetic layer formed on the pinned magnetic layer separated by a nonmagnetic interlayer therebetween; and bias layers for orienting the magnetization vector of the free magnetic layer in a direction substantially orthogonal to the magnetization vector of the pinned magnetic layer, wherein the antiferromagnetic layer and the pinned magnetic layer comprise an exchange coupling film according to claim 1, the pinned magnetic layer corresponding to the ferromagnetic layer. 13. A magnetoresistive element comprising: an antiferromagnetic layer; a pinned magnetic layer in contact with the antiferromagnetic layer, the magnetization vectors of the pinned magnetic layer being pinned by an exchange anisotropic magnetic field generated in relation with the antiferromagnetic layer; a free magnetic layer formed on the pinned magnetic layer separated by a nonmagnetic interlayer; and antiferromagnetic exchange bias layers formed above or under the free magnetic layer, the exchange bias layers being separated from one another in a track width direction by a gap therebetween, wherein the exchange bias layers and the free magnetic layer comprise an exchange coupling film according to claim 1, the exchange bias layers corresponding to the antiferromagnetic layer and the free magnetic layer corresponding to the ferromagnetic layer. 14. A magnetoresistive element comprising: nonmagnetic interlayers provided above and below a free magnetic layer; pinned magnetic layers, one thereof being provided on the pinned magnetic layer formed on the free magnetic layer and the other being provided under the pinned magnetic layer formed under the free magnetic layer; antiferromagnetic layers for pinning the magnetization vectors of the pinned magnetic layers, one of the antiferromagnetic layers being provided on one of the pinned magnetic layers and the other being provided under the other of the pinned magnetic layers; and bias layers for orienting the magnetization vector of the free magnetic layer in a direction substantially orthogonal to the magnetization vector of the pinned magnetic layer, wherein the antiferromagnetic layer and the pinned magnetic layer in contact with the antiferromagnetic layer comprise an exchange coupling film according to claim 1, the pinned magnetic layer corresponding to the ferromagnetic layer. 15. A magnetoresistive element comprising: a magnetoresistive layer; a soft magnetic layer provided on the magnetoresistive layer separated by a nonmagnetic layer therebetween; and antiferromagnetic layers provided above or below the magnetoresistive layer, the antiferromagnetic layers being separated from one another in a track width direction with a gap therebetween, wherein the antiferromagnetic layer and the magnetoresistive layer comprise an exchange coupling film according to claim 1, the magnetoresistive layer corresponding to the ferromagnetic layer. 16. An exchange coupling film comprising an antiferromagnetic layer and a ferromagnetic layer in contact with the antiferromagnetic layer, in which an exchange coupling magnetic field generated at the interface between the antiferromagnetic layer and the ferromagnetic layer orients the magnetization vector of the ferromagnetic layer in a particular direction, wherein diffraction spots corresponding to reciprocal lattice points indicative of crystal planes of the antiferromagnetic layer and the ferromagnetic layer appear in transmission electron beam diffraction diagrams of the antiferromagnetic layer and the ferromagnetic layer obtained using an electron beam in a direction parallel to the interface, wherein first imaginary lines in the diffraction diagrams of the antiferromagnetic layer and the ferromagnetic layer, the first imaginary lines each connecting a beam origin and a particular one of the diffraction spots which is given the same label in both the diffraction diagrams of the antiferromagnetic layer and the ferromagnetic layer and is located in a layer thickness direction when viewed from the beam origin, are coincident with each other, and wherein a particular diffraction spot indicative of a particular crystal plane, located in a direction other than the layer thickness direction, appears only in one of the diffraction diagrams of the antiferromagnetic layer and the ferromagnetic layer. 17. An exchange coupling film according to claim 16, wherein the diffraction spots located in the layer thickness direction are assigned to the {111} planes. 18. An exchange coupling film according to claim 16, wherein the antiferromagnetic layer and the ferromagnetic layer are deposited in that order from the bottom, the exchange coupling film further comprising a seed layer provided below the antiferromagnetic layer, the seed layer mainly having a face-centered cubic structure and having the crystallographically identical planes generically described as the {111} planes, one of which is preferentially aligned parallel to the interface. 19. An exchange coupling film according to claim 18, the seed layer comprising one of a NiFe alloy and a Ni--Fe--Y alloy, wherein Y is at least one element selected from the group consisting of Cr, Rh, Ta, Hf, Nb, Zr, and Ti. 20. An exchange coupling film according to claim 18, wherein the seed layer is nonmagnetic at room temperature. 21. An exchange coupling film according to claim 18, further comprising an underlayer provided under the seed layer, the underlayer comprising at least one element selected from the group consisting of Ta, Hf, Nb, Zr, Ti, Mo, and W. 22. An exchange coupling film according to claim 18, wherein at least part of the interface between the antiferromagnetic layer and the seed layer is in a lattice-mismatching state. 23. An exchange coupling film according to claim 16, the antiferromagnetic material further comprising X', wherein X' is at least one element 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, and rare earth elements. 24. An exchange coupling film according to claim 23, wherein the antiferromagnetic material is an interstitial solid solution in which X' is inserted to interstices in the lattice formed by X and Mn or a substitutional solid solution in which X' partly displaces the lattice points in the crystal lattice formed by X and Mn. 25. An exchange coupling film according to claim 24, wherein the X or X+X' content in the antiferromagnetic material is in the range of 45 to 60 atomic percent. 26. An exchange coupling film according to claim 16, wherein at least part of the interface between the antiferromagnetic layer and the ferromagnetic layer is in a lattice-mismatching state. 27. A magnetoresistive element comprising: an antiferromagnetic layer; a pinned magnetic layer in contact with the antiferromagnetic layer, the magnetization vector of the pinned magnetic layer being pinned by an exchanged anisotropic magnetic field generated in relation to the antiferromagnetic layer; a free magnetic layer formed on the pinned magnetic layer separated by a nonmagnetic interlayer therebetween; and bias layers for orienting the magnetization vector of the free magnetic layer in a direction substantially orthogonal to the magnetization vector of the pinned magnetic layer, wherein the antiferromagnetic layer and the pinned magnetic layer comprises an exchange coupling film according to claim 16, the pinned magnetic layer corresponding to the ferromagnetic layer. 28. A magnetoresistive element comprising: an antiferromagnetic layer; a pinned magnetic layer in contact with the antiferromagnetic layer, the magnetization vectors of the pinned magnetic layer being pinned by an exchange anisotropic magnetic field generated in relation to the antiferromagnetic layer; a free magnetic layer formed on the pinned magnetic layer separated by a nonmagnetic interlayer; and antiferromagnetic exchange bias layers formed above or under the free magnetic layer, the exchange bias layers being separated from one another in a track width direction by a gap therebetween, wherein the exchange bias layers and the free magnetic layer comprise an exchange coupling film according to claim 16, the exchange bias layers corresponding to the antiferromagnetic material and the free magnetic layer corresponding to the ferromagnetic layer. 29. A magnetoresistive element comprising: nonmagnetic interlayers provided above and below a free magnetic layer; pinned magnetic layers, one thereof being provided on the pinned magnetic layer formed on the free magnetic layer and the other being provided under the pinned magnetic layer formed under the free magnetic layer; antiferromagnetic layers for pinning the magnetization vectors of the pinned magnetic layers, one of the antiferromagnetic layers being provided on one of the pinned magnetic layers and the other being provided under the other of the pinned magnetic layers; and bias layers for orienting the magnetization vector of the free magnetic layer in a direction substantially orthogonal to the magnetization vector of the pinned magnetic layer, wherein the antiferromagnetic layer and the pinned magnetic layer in contact with the antiferromagnetic layer comprise an exchange coupling film according to claim 16, the pinned magnetic layer corresponding to the ferromagnetic layer. 30. A magnetoresistive element comprising: a magnetoresistive layer; a soft magnetic layer provided on the magnetoresistive layer separated by a nonmagnetic layer therebetween; and antiferromagnetic layers provided above or below the magnetoresistive layer, the antiferromagnetic layers being separated from one another in a track width direction with a gap therebetween, wherein the antiferromagnetic layer and the magnetoresistive layer comprise an exchange coupling film according to claim 16, the magnetoresistive layer corresponding to the ferromagnetic layer.