Effect of acceptor co-doping on magnetism and electronic states in ferromagnetic semiconductor (Zn,Cr)Te

Abstract

The magnetic properties and the electronic states were investigated for a magnetic semiconductor (Zn,Cr)Te co-doped nitrogen (N) as an acceptor impurity. A series of N-doped Zn1-xCrxTe thin films with Cr compositions in the range of x = 0.06-0.09 and N concentrations in the range of [N] = 1018-1020 cm-3 were grown by molecular beam epitaxy (MBE), and the magnetization measurement using superconducting quantum interference device (SQUID) magnetometer and the X-ray absorption fine structure (XAFS) measurements were performed. As a result, the disappearance of ferromagnetic behaviors and the change in X-ray absorption near edge structure (XANES) spectra were observed at almost the same nitrogen concentration around [N] = 1 × 1020 cm-3. This correlated change in the magnetic properteis and the Cr electronic states was discussed in relation to a decrease of the electron density in the 3d impurity level due to the N co-doping. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.