Growth of all-epitaxial Co2MnSi/Ge/Co2MnSi vertical spin-valve structures on Si

We explore epitaxial growth of Co2MnSi/Ge/Co2MnSi vertical spin-valve structures on Si, where the Co2MnSi (CMS) is expected to be a half-metallic material for spintronics. By combining solid phase epitaxy, low-temperature molecular beam epitaxy, and atomic layer termination techniques, we can grow an epitaxial Ge layer on CMS at 250 °C, where the atomic interdiffusion between Ge and CMS is suppressed. After further optimization of the growth condition of the Ge intermediate layer, all-epitaxial CMS/Ge/CMS vertically stacked structures with spin-valve like magnetization reversal processes are demonstrated. This vertically stacked structures can be utilized for vertical spin-valve devices with a Ge channel on Si.