Influence of the Ge diffusion on the magnetic and structural properties in Fe3Si and CoFe epilayers grown on Ge

Abstract

We study epitaxial growth and magnetic properties of ferromagnetic alloys, Fe3Si and CoFe, on low-temperature-grown germanium (LT–Ge) layers. Despite high-quality epitaxial growth of Fe3Si and CoFe layers on Ge substrates, the structural and magnetic characteristics of Fe3Si layers are significantly degraded only when the growth is conducted on LT–Ge. We clarify that the degradation is induced by the diffusion of Ge atoms into Fe3Si. Since high-quality CoFe layers can be obtained even on LT–Ge, there is no Ge diffusion into CoFe. It is important for vertical Ge spintronics devices to understand the mechanism of the suppression of the Ge diffusion into the ferromagnetic materials.