Epitaxial growth of diluted magnetic semiconductor Ge_(1-x)Cr_xTe with high Cr composition

摘要

Ⅳ-Ⅵ diluted magnetic semiconductor Ge_(1-x)Cr_xTe layers up to x = 0.1 were grown on SrF_2 substrates by molecular beam epitaxy. In situ reflection high-energy electron diffraction shows a streaky pattern with a sixfold symmetry in the plane for the Ge_(1-x)Cr_xTe layer, implying an epitaxial growth of Ge_(1-x)Cr_xTe (111)/SrF_2 (111). A clear hysteresis loop is observed in the anomalous Hall effect measurements due to the strong spin-orbit interaction in the host GeTe. The Curie temperature increases with increasing Cr composition up to 200 K, but there is no clear dependence of the Curie temperature on the hole concentration, implying that the mechanism of the ferromagnetic interaction among Cr ions is different from Mn doped diluted magnetic semiconductors.