Properties of Manganese-Permalloy Films

Abstract

Thin ferromagnetic films of Ni-Fe-Mn alloys with nominal manganese contents of 3%, 5%, 8%, and 12% have been prepared from alloy cathodes by bias sputtering. The resulting film compositions selected closely parallel the null magnetostriction contour in the ternary composition diagram. The effects of substrate temperature (100°−350°C) and film thickness (500–1200 Å) on wall-motion threshold H0, anisotropy field Hk0, dispersion α90, skew Δβ, and magnetostriction have been experimentally determined. The following conclusions can be drawn from the data: (1) There is a minimum-film bias potential at which uniform films exhibiting low dispersion of the easy axis are obtained. (2) For constant thickness and substrate temperature, H0 and Hk0 decrease with increasing manganese content. (3) For constant H0/Hk0 ratio, angular dispersion increases with increasing manganese content. (4) The alloys containing 3% and 5% Mn show the typical dependence of H0 and Hk0 on deposition temperature (i.e., H0 increases and Hk0 decreases with increasing deposition temperature). (5) For films of the 8% Mn alloy, H0 is relatively insensitive to deposition temperature. (6) For films of the 12% Mn alloy, H0 decreases with increasing deposition temperature.

Some Aspects of Deposition Parameters of RF Sputtered Ferromagnetic Film Germane to the Study of Magnetoresistive Sensing Devices

“…Similar results for nickel-iron-manganese films have been reported by Greist and Flur [22] for r.f sputtered films under d.c bias conditions. The lower coercivities at the bias potentials may be attributed to the improvement in film microstructure due to reduced impurity concentrations.…”