The magnetic properties of Co-Ni-Fe films

Abstract

H_{k} , \deltaH_{k} ,\alpha_{90} and H c have been measured for vapor-deposited nonmagnetostrictive Co-Ni-Fe films, 1500 A thick. All parameters except H c have been measured using the transverse-biased permeability apparatus. H k increases linearly with cobalt melt content up to 15-percent cobalt, \deltaH_{k} and H c increase with increasing cobalt and substrate temperature. α 90 decreases in the region 0-15-percent cobalt and then increases with increased cobalt melt content and substrate temperature. The coefficient of magnetoelastic composition sensitivity S is the slope of the curve η versus the ratio of nickel to iron in the melt for a constant cobalt percentage about the point \eta = 0 . The value of S increases rapidly with substrate temperature to a maximum near 300°C if the cobalt percentage is small. For larger amounts of cobalt S is reduced and is more independent of temperature. It is proposed that the volume fraction and the mobility of the grain boundaries in the film structure are primarily responsible for S .