Epitaxial growth of Co₂ MnSi thin films at the vicinal surface of n-Ge(111) substrate

The structure and magnetic properties of Co₂ MnSi films on n-Ge(111) substrate were investigated for the motivation of spin injection. The 50-nm-thick Co₂ MnSi films were fabricated on n-Ge(111) substrates by dc sputtering and postannealed about 1 h at the various temperatures ranging from 200-500 °C. In the annealing temperature range of 300-400 °C, the Co₂ MnSi were grown epitaxially at the vicinal surface of n-Ge(111) substrates. The epitaxial layer of Co₂ MnSi films was about 18 nm thick at 350 °C and exhibited ferromagnetic behavior. Interestingly, there was no diffusion of Ge inside the epitaxial layer and atomically flat interface was obtained.