Suppression of ferromagnetism due to hole doping in Zn 1 − x Cr x Te grownby molecular-beam epitaxy

• Published in: Applied physics letters 2005-11, Vol.87 (19), p.192116-192116-3
• Main Authors: Ozaki, N., Okabayashi, I., Kumekawa, T., Nishizawa, N., Marcet, S., Kuroda, S., Takita, K.
• Format: Article
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.2130387

Electric and magnetic properties were investigated on p -type Zn 1 − x Cr x Te doped with nitrogen (N) as an acceptor. Thin films of p - Zn 1 − x Cr x Te ( 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 Zn 1 − x Cr x Te 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 3 d impurity level formed in the band gap of ZnTe.