Magnetic Properties of Ni-Fe-Cr Films

Abstract

Films of Ni-Fe-Cr were vapor deposited on heated glass substrates in vacuum. In each preparation increasing amounts of Cr were added to the original Ni-Fe source, and a fresh set of glass substrates was exposed to the vapor beam after each Cr addition. In this way, Cr contents ranging from 0% to about 5% were produced in different films in each preparation, while Ni-Fe ratios of various preparations ranged from 78% Ni, 22% Fe to 90% Ni, 10% Fe. For all Ni-Fe ratios the anisotropy field Hk, the magnetization M, and the wall coercive force Hw, decreased monotonically with Cr content, while angular dispersion and electrical resistivity ρ increased with Cr content. The variations of M and ρ with Cr content were consistent with bulk data. The empirical relation Hk=A(M-B) was found valid except for very small or very large additions of Cr; the constants A and B were independent of the initial Ni-Fe ratio but dependent on the substrate temperature. Addition of Cr always tended to make the magnetostriction more positive, regardless of the initial Ni-Fe ratio.