Suppression of ferromagnetism due to hole doping in Zn1-xCrxTe grown by molecular-beam epitaxy -: art. no. 192116

Electric and magnetic properties were investigated on p-type Zn1-xCrxTe doped with nitrogen (N) as an acceptor. Thin films of p-Zn1-xCrxTe (x <= 0.09) were grown by molecular-beam epitaxy with the supply of N-2 gas excited by rf plasma. With the increase of Cr composition x at an almost fixed N concentration of the order of 10(20) cm(-3), the temperature dependence of resistivity changed from metallic behavior to an insulating one, accompanied with a significant decrease of the hole concentration. The magnetization measurements revealed that ferromagnetic behaviors observed in undoped Zn1-xCrxTe were suppressed due to the nitrogen doping; with N concentrations of the order of 10(20) cm(-3), hysteresis loops in the magnetization curve disappeared, the magnitude of magnetization decreased, and the ferromagnetic transition were not observed down to 2 K according to the Arrott plot analysis. These experimental findings are discussed on the basis of the ferromagnetic double exchange interaction which is considered to work on the Cr 3d impurity level formed in the band gap of ZnTe. (C) 2005 American Institute of Physics.