Single-Crystalline Ferromagnetic Alloy Semiconductor Ge1-xMnx Grown on Ge(111)

We investigate the structural and magnetic properties of Ge1-xMnx films grown on Ge(111) substrates. The Ge1-xMnx films prepared with appropriate epitaxial growth conditions are diamond-type single crystals with a homogeneous Mn distribution. Magnetic circular dichroism (MCD) spectra exhibit enhanced peaks at the critical point energy E-1 of Ge, with single-phase ferromagnetism. The MCD characteristics are consistent with magnetization data, and the Curie temperature increases with the Mn content x. These results indicate that the Ge1-xMnx films grown on Ge(111) are intrinsic ferromagnetic alloy semiconductors. (C) 2010 The Japan Society of Applied Physics