Structure and ferromagnetic resonance of Tb/FeCo multilayer thin films

Abstract

Multilayer thin films of Tb and Fe95Co5 were prepared by thermal evaporation from two sources. The films were studied by x‐ray diffraction, Auger electron spectroscopy, and ferromagnetic resonance. The low‐angle x‐ray diffraction and Auger analysis showed that a multilayer structure was achieved for films with a modulation wavelength Λ≥31.5Å. FMR results were consistent with the structural data. The films with Λ≤31.5Å had similar HKeff, line width, and line shape to those of a coevaporated alloy with the same composition. The films with Λ≫31.5 Å had an HKeff greater than or equal to that of an Fe95Co5 film. A film with HKeff greater than that of the Fe95Co5 film had multiple resonances. Interfacial stress due to incoherent matching of the Tb and Fe95Co5 layers is thought to give rise to differences in HKeff in the various layers.