Magnetic measurements on the layered III–VI diluted magnetic semiconductor Ga1−xFexSe

Magnetic properties of single crystalline Ga12xFexSe have been measured. This material is in the new class of diluted magnetic semiconductors based on the III±VI semiconductors. The magnetization versus ®eld for an x50.05 sample deviates from the linear response seen previously in Ga12xMnxSe and Ga12xMnxS and reaches a maximum of 0.12 emu/g ~,7% of the expected saturation value! at1.8Kin7T.Ga12xFexSe exhibits an anisotropy below 2 T from 5 to 400 K with the hard axis perpendicular to the GaSe planes. Neither the broad peak observed from 119±195 K in Ga12xMnxSe nor the Curie-Weiss behavior observed above 75 K in Ga12xMnxS are observed in Ga12xFexSe. The sharp cusp at 10.9 K in Ga12xMnxS ~characteristic of longer range ordering! is also not observed in Ga12xFexSe in temperatures down to 1.8 K. In 0.1 T in temperatures between 50 and 400 K, the magnetization drops to a roughly constant 0.004 emu/g. Below 5 K, the magnetization approaches a constant value of approximately 0.12 emu/g. The magnetic behavior of Ga12xFexSe is consistent with Van Vleck paramagnetism. © 2001 American Institute of Physics. @DOI: 10.1063/1.1357843#