Structural and magnetic properties of Ge1-xMnx/Ge(001) 2x1 diluted magnetic semiconductors

Structural and magnetic properties of Ge1-xMnx alloys, epitaxially grown on a Ge(001)2 x 1 surface have been investigated. We prepared Ge1-xMnx films by MBE as a function of substrate temperature and Mn concentration x. In-situ RHEED was used to monitor the streaks of the Ge1-xMnx epitaxial films. The optimal temperature, to obtain a very well-ordered epitaxial Ge1-xMnx alloy, for Mn concentrations of x = 0.02, and x = 0.04, was found to be 525 K. Ex-situ magneto-optical Kerr effect and XMCD at the L-2/3 Mn2p absorption edges on Ge1-x Mn-x films, show isotropic magnetic properties. The Curie temperature of about 270 K was found on most of the ordered samples.