Abstract
The grain diameter dependence of the coercivity for FeAlSi films was studied. Investigation of the film structures by means of X-ray diffraction and TEM showed that films, with a composition of 11.7 w%Nb-5.9 Al-8.4Si and balancing Fe, had a uniform fine grain crystal structure of 20 nm after a heat treatment at 500°C; in this case a low coercivity of 0.70e was obtained. On the other hand, for FeAlSi films evaporated in an Ar gas atmosphere, the grain size changed from 150 nm to 50 nm as the Ar gas pressure increased, and the coercivity was roughly proportional to the inverse of the grain diameter above a certain diameter of around 60 nm. The behavior can be qualitatively explained by the model proposed by Herzer, on the assumption that both the crystalline magnetic anisotropy and the exchange stiffness of the FeAlSi films are considerably small compared with those of a pure Fe film.
