Compositional dependencies of ferromagnetic Ge1−xMnxTe grown by solid-source molecular-beam epitaxy

Abstract

The IV-VI diluted magnetic semiconductor Ge1−xMnxTe thin films on BaF2 (111) substrate have been prepared using solid-source molecular-beam epitaxy technique by varying the Mn concentrations from x=0.25 to 0.98. The chemical Mn concentration was determined by x-ray photoelectron spectroscopy measurement. The in situ reflection high-energy electron diffraction pattern indicates that the growth mechanism is in the island-growth mode. The x-ray diffraction shows that the Ge1−xMnxTe films crystallize in the NaCl phase with (111) orientation. A clear ferromagnetic ordering is observed in the detailed temperature-dependent magnetization measurement for 0.25<x<0.98. The dependence of Curie temperature TC on Mn concentration x tends to follow a quadratic behavior. This phenomenon can be attributed to the increase of antiferromagnetic interaction since MnTe is an antiferromagnet.