| 摘要 |
PROBLEM TO BE SOLVED: To prevent lowering of an exchange coupling magnetic field due to heat treatment, by changing the crystal phase state of a magnetization fixed layer adjacent to a ferromagnetic layer in the direction of film thickness, and forming a phase exhibiting antiferromagnetism in a portion near the ferromagnetic layer and a phase of a low Neel temperature mainly in a portion far from the ferromagnetic layer. SOLUTION: An exchange coupling film is formed by sequentially stacking an underlying layer 2 made of a high melting point material such as Ta, a ferromagnetic layer 3 made of a NiFe alloy or the like, a magnetization fixed layer 4 made of a MnPt alloy and a protective layer 5 on a heat substrate 1 made of glass, Si, or altic or the like having Al2 O3 formed on a substrate. The magnetization fixed layer 4 after film formation has a MnPt alloy ofγ-phase on the side of the ferromagnetic layer 3 and a MnPt alloy ofα-phase on the opposite side. Finally, a Ta film of 50Åis formed as the protective layer 5. In this exchange coupling film the crystal phase of the magnetization fixed layer which exchange-couples with the ferromagnetic layer isγ-Mn phase in a portion close to the ferromagnetic layer and isα-Mn phase in a portion far from the ferromagnetic layer.
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