Structural, magnetic, and transport properties of (Zn,V)Te semiconductors

Vanadium-doped ZnTe has been predicted to be one of the candidates for ferromagnetic semiconductors with a high Curie temperature [K. Sato and H. Katayama-Yoshida, Semicond. Sci. Technol. 17, 367 (2002)]. In this paper, we report the structural, magnetic, and transport properties of (Zn,V)Te films prepared by magnetron sputtering. Samples were fabricated on both GaAs and thermally oxidized silicon substrate at elevated temperature. Oriented sample (100) can be achieved on GaAs substrates and only polycrystalline samples are observed on Si substrates. X-ray diffraction (XRD) and transmission electron spectroscopy (TEM) show no magnetic precipitates in the (Zn,V)Te film. The magnetization measurement shows that the oriented sample is paramagnetic at 5 K, while films on Si substrate shows weak ferromagnetism at 5 K. The sign of magnetoresistance (MR= [R(H)-R(0)] R(0)) gradually changes from negative to positive with temperature, and positive MR at high temperatures shows H2 dependence, indicating ordinary MR effect. It is believed the observed negative MR corresponds to the ferromagnetic ordering at lower temperature.