Growth and magnetic properties of novel ferromagneticsemiconductor (Zn, Cr)Te

Magnetic properties of a novel ferromagnetic semiconductor (Zn, Cr)Te were investigated. Zn1−xCrxTe thin films, both without and with the additional hole doping by nitrogen, were grown by molecular beam epitaxy. In the magnetization measurement on Zn1−xCrxTe without carrier doping, the ferromagnetic behaviors such as a hysteresis loop in the magnetization vs. magnetic field curve were observed. Similar hysteretic behaviors in the field dependence were reproduced in the magnetic circular dichroism measurement. The ferromagnetic transition temperature TC deduced from Arrott plot increased almost linearly with Cr composition with the maximum TC=275 K at a Cr composition of x=0.17. The ferromagnetic behaviors observed in the undoped samples were found to be suppressed upon the p-type doping with nitrogen. These experimental findings are discussed based on the double exchange mechanism and the suppression of ferromagnetism by the hole doping is interpreted as due to the shift of the Fermi level in the Cr 3d level with the acceptor doping.