ESR study of diluted magnetic semiconductor (Ga,Cr)As

Epitaxial film of (Ga,Cr)As were successfully grown by low temperature molecular beam epitaxy method up to Cr concentration of 2.7 %. Magnetization curves showed that weak paramagnetic behavior at low temperatures. Electron spin resonance (ESR) measurements were carried out in order to investigate electronic states and local environment of Cr ion using X-band spectrometer at low temperatures. A broad ESR signal around 510 mT was observed at 4.5 K. From angular dependence of the resonance field, this signal was assigned to the compensated Cr²⁺(3d⁴) center.