ESR Study of Novel Room-Temperature Ferromagnetic Semiconductors Pb_(1-x-y)Sn_xCr_yTe

摘要

We report on the magnetic properties of novel diluted magnetic semiconductors Pb_(1-x-y)Sn_xCr_yTe revealing ferromagnetism at temperatures higher than room temperature. Depending on chromium concentration the Curie temperature varies in a wide range (150÷360 K) and effective magnetic moment achieves 1μ_B upon an increase of chromium doping level. Electron spin resonance (ESR) spectra in the paramagnetic phase were satisfactory approximated by a single Dysonian line. Effective g-factor tends to the saturation value g=2.08±0.01, while the linewidth passes through a minimum in the vicinity of magnetic ordering transition and then broadens with an increase of the temperature. In ferromagnetic phase the pronounced distortion and splitting of the ESR spectra into two lines occurs due to additional ferromagnetic contribution to absorption.