Film growth of Ge1-xMnxTe using ionized-cluster beam technique

IV-VI diluted magnetic semiconductor Ge1-xMnxTe of NaCl crystal structure is successfully obtained with the Mn concentration x up to x = 0.96 using ionized-cluster beam technique. The (1 1 1) plane of Ge1-xMnxTe is grown epitaxially parallel to the (1 1 1) plane of BaF2 substrate. The lattice constant of Ge1-xMnxTe decreases with the increase of Mn concentration. At the Curie temperature(T-c), ferromagnetic phase transition occurs as the result of Runderman-Kittel-Kasuya-Yoshida (RKKY) interaction. The highest T-c in this study is 140 K for x = 0.51. Temperature dependence of spontaneous magnetization suggests the existence of multiple exchange interactions. The distinct magnetic anisotropy is not observed in the magnetization curves applying the magnetic field parallel and perpendicular to the plane. The obtained demagnetizing factor is 0.52, which was smaller than that of the thin film. It can be ascribed to the non-uniform magnetization state. (C) 2001 Elsevier Science B.V. All rights reserved.