TURKISH JOURNAL OF PHYSICS, cilt.44, ss.67-76, 2020 (ESCI İndekslerine Giren Dergi)
We investigated the effects of crystalline order on the structural and magnetic properties of ultrathin Mn-doped Ge thin films grown by thermal diffusion. The dopant motion which occurs during the annealing stage appears to differ considerably depending upon whether the Ge layer is in a crystalline or an amorphous state. The details of the temperature-dependent magnetization curves reveal that the a-MnGe and c-MnGe films show ferromagnetic property up to 300K and similar to 250K, respectively. Ferromagnetic Mn5Ge3 thin film with weakly anisotropic in-plane magnetization is formed on amorphous Ge thin film, while weakly ferromagnetic Mn5Gex Si3-x nanostructures are developed on crystalline Ge thin film due to diffusion of Mn atoms through the Ge layer and interact with Si substrate.