Magnetic and structural characterizations of HCP permalloy films grown by molecular beam epitaxy

Abstract

An hep metastable phase of Ni80Fe20(1100) structure has been grown as high-quality epitaxial films on Co(1100) and Cr(211) planes. The epilayers of Ni80Fe20 grow as hep structure up to a critical thickness of ∼100 Å, and the further layers transform to twinned fee structure. Magneto-optical Kerr effect study indicates that the hep Ni80Fe20(1100) layers exhibit strong crystalline induced uniaxial magnetic anisotropy with easy axis along the hcp[0001] direction. The subsequent fee Ni80Fe20 layers show decreasing coercive fields as the film thickness increased. For the thick fee film, interestingly, the magnetic easy axis shifts 90° with respect to that of the underlying hep layers. The result is explained by the shape anisotropy effect due to the formation of quasi-1D columnar islands directed perpendicular to the hcp[0001] direction. © 1998 American Institute of Physics.