Morphological and magnetic properties of Ge/MnxGe1-x/Ge(0 0 1)2 × 1 diluted magnetic semiconductor

We studied morphological and magnetic properties of Ge/MnxGe1-x/Ge(0 0 1)2 × 1, x = 0.02–0.04. Several MnxGe1-x alloys were grown on Ge(0 0 1)2 × 1 by molecular beam epitaxy, as a function of substrate temperature and Mn concentration. The samples were characterized in situ by RHEED, and ex situ by energy dispersive X-ray reflectivity (EDXR) and magneto-optical Kerr effect, (MOKE). From RHEED analysis we found an optimal growth temperature Tepi = 523 K to achieve 2D epitaxial MnxGe1-x (x = 0.02–0.04) alloy on a Ge(0 0 1) substrate. X-ray reflectivity measurements provided: the film roughness, the MnxGe1-x scattering length density, and the average thickness for all samples. MOKE analysis showed ferromagnetism with Curie temperature TC = 270 K for samples grown at Tepi = 523 K.