Substrate-induced magnetic ordering of rare-earth overlayers: II

Abstract

For pt.I see Phys. Rev. B, vol.43, p.3171 (1991). In earlier studies, it was found that for terbium overlays on Ni(111) and Fe(100), the substrates induced some ferromagnetic ordering in the rare-earth film, at temperatures above the Tb Curie temperature. A study is given of the magnetization of ferromagnetic films on ferromagnetic substrates, at temperatures below both Curie temperatures. Expansions are developed for the magnetization within the film as a power series in the distance z to the interface, using Ginzburg-Landau theory. Empirical data for Tb and gadolinium films are found to be consistent with the general form of the expressions found from the theory. Relations are derived for the observed expansion coefficients in terms of the Ginzburg-Landau parameters of the film material. The form a/z for the magnetization is predicted to represent the magnetization well, for z located in an experimentally accessible range of values; data for the magnetization are consistent with this form.