Magnetic properties of Mn doped crystalline and amorphous Ge thin films grown on Si (111)

Abstract

We investigated the effects of crystalline order on the structural and magnetic properties of ultrathin MndopedGe thin films grown by thermal diffusion. The dopant motion which occurs during the annealing stage appearsto differ considerably depending upon whether the Ge layer is in a crystalline or an amorphous state. The details of thetemperature-dependent magnetization curves reveal that the a-MnGe and c-MnGe films show ferromagnetic property upto 300K and ~250K, respectively. Ferromagnetic Mn5 Ge3 thin film with weakly anisotropic in-plane magnetizationis formed on amorphous Ge thin film, while weakly ferromagnetic Mn5 Gex Si3−x nanostructures are developed oncrystalline Ge thin film due to diffusion of Mn atoms through the Ge layer and interact with Si substrate.