Changes in the local structure of amorphous Tb-Fe observed by magnetic anisotropy measurements

Abstract

Thin films of ferrimagnetic metallic amorphous Tb-Fe show an abrupt and dramatic change in the magnetic anisotropy, an extremely sensitive probe of local structure, at a composition which is also the magnetic compensation composition. The anisotropy of Tb-rich films is uniaxial and is believed to be the result of preferential pairs formed along the film growth direction. By contrast, detailed measurements of the magnetic anisotropy of Fe-rich films grown at room temperature and above have shown that the anisotropy requires a complex form which implies the presence of a second phase. The anisotropy also shows that the formation of this second phase depends on the deposition temperature; Fe-rich films grown at 77 K possess simple uniaxial anisotropy.