Ferromagnetic semiconductor Ge1−xCrxTe with a Curie temperature of 180K

A IV-VI ferromagnetic semiconductor Ge1−xCrxTe (x∼0.06) with Curie temperature TC up to 180K is grown by molecular-beam epitaxy. The magnetization is well reproduced from anomalous Hall effect. As the Te∕Cr flux ratio increases during the growth of Ge1−xCrxTe, the spontaneous magnetization and the magnetic anisotropy are decreased and TC is increased. On the other hand, the Te∕Cr flux ratio over 3.6 leads to formation of Cr–Te precipitations. The magnetoresistance measurements reveal that the increase of TC is attributed to the decrease of nonstoichiometric defects.