Optical, magnetic, and transport behaviors of Ge1-xMnxTe ferromagnetic semiconductors grown by molecular-beam epitaxy.

The optical, magnetic, and transport behaviors of Ge_1-xMn_xTe (x=0.24 and 0.55) grown by solid-source molecular-beam epitaxy are investigated. X-ray diffraction shows that Ge_1-xMn_xTe crystallizes in rocksalt structure. The temperature-dependent magnetization (M-T) for x=0.55 sample gives a Curie paramagnetic temperature of θ_p∼180 K, which is consistent with the temperature-dependent resistivity ρ(T) measurement. Anomalous Hall effect is clearly observed in the samples and can be attributed to extrinsic skew scattering based on the scaling relationship of ρ_xy∝ρ_xx^1.06. The magnetoresistance of Ge_1-xMn_xTe is isotropic and displays a clear hysterestic loop at low temperature, which resembles that of giant-magnetoresistance granular system in solids. [ABSTRACT FROM AUTHOR]