Morphological and magnetic properties of Ge/MnxGe1-x/Ge(001)2 x 1 diluted magnetic semiconductor

We studied morphological and magnetic properties of Ge/MnxGe1-x/Ge(0 0 1)2 x 1, x = 0.02-0.04. Several MnxGe1-x alloys were grown on Ge(0 0 1)2 x I 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 T-epi = 523 K to achieve 2D epitaxial MnxGe1-x (x = 0.02-0.04) alloy on a Ge(001) 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 T-C = 270 K for samples grown at T-epi = 523 K. (c) 2006 Elsevier B.V. All rights reserved.