Magnetic Anisotropy of NiMn/Ni and NiMn/Cu/Ni Thin Films

The magnetic anisotropy of reentrant spin glass NiMn thin film, in the vicinity of the ferromagnetic Ni film, is investigated using NiMn/Ni, Cu/Ni/Cu (t=10 Å and 500 Å)/NiMn and NiMn/Ni/Cu (t=10 ÷ 5000 Å)/Ni films. The unidirectional anisotropy field of NiMn layer in NiMn/Ni film is smaller than that of bulk NiMn. In Cu/Ni/Cu (t=10 Å and 500 Å)/NiMn film, the unidirectional anisotropy field is almost independent of the Cu spacer thickness. These results can be explained in terms of magnetic coupling between the magnetic layers in addition to the film structure of NiMn layer.