Magnetic behaviors of ferromagnetic semiconductor Zn1-xCrxTe grown by MBE

The magnetic and structural properties of NIBE-grown films of Zn1-xCrxTe were investigated. The magnetization versus magnetic field (M-H) measurement of Zn1-xCrxTe (x = 0.01-0.17) showed clear hysteresis loop at low temperatures. The ferromagnetic transition temperature (T-C) estimated from the Arrott-plot analysis increased almost linearly with the Cr composition (x) up to 275 K at x = 0.17. However, in the magnetization versus temperature (M-T) measurement, the irreversibility between the zero-field-cooled (ZFC) and field-cooled (FC) processes was observed. This is typically observed in the magnetic random system such as spin-glass or superparamagnetic phase. In the high resolution transmission microscopy (HRTEM) observations, structural defects such as stacking faults and polycrystalline-like structure were observed at high Cr compositions, whereas any apparent precipitates of different phases were not seen in all the range of Cr compositions examined. The correlation of the observed magnetic randomness with the local structural defects was discussed.