Author(s): Xie, ZC (Xie, Zhicheng); Meng, GC (Meng, Gengchen); Wen, LJ (Wen, Lianjun); Zhao, ZY (Zhao, Zhiyuan); Sun, HL (Sun, Hongli); Qin, HR (Qin, Hongrui); Pan, D (Pan, Dong); Wang, HL (Wang, Hailong); Wei, DH (Wei, Dahai); Zhao, JH (Zhao, Jianhua)

Source: PHYSICAL REVIEW B Volume: 109 Issue: 2  Article Number: 024407  DOI: 10.1103/PhysRevB.109.024407  Published Date: 2024 JAN 9 

Abstract: The group-IV Ge1-xMnx ferromagnetic semiconductor (FMS) has attracted much interest in spintronics due to its compatibility with semiconductor technology. However, Ge1-xMnx FMS prepared at high growth temperature (TS) meets dilemmas in balancing solubility and intermetallic precipitates, limiting its Curie temperature (TC) and electrical tunability. In this study, Ge1-xMnx films were prepared by magnetron sputtering at low TS combined with rapid thermal annealing (RTA). We conducted a systematic study of the microstructure, valence state, and magnetic properties of Ge1-xMnx films. The phase diagram of Ge1-xMnx films versus Mn composition x and RTA temperature TR was plotted, and face-centered cubic structure Ge1-xMnx FMS was achieved with x up to 0.1. As x increased, the hole-mediated ferromagnetism of Ge1-xMnx FMS was enhanced, with the TC reaching 282 K at x = 0.07. We found that the magnetoresistance ratio of Ge1-xMnx FMS was significantly smaller than that of Ge1-xMnx with intermetallic precipitates by two orders, providing an easy method to confirm Ge1-xMnx FMS without intermetallic precipitates. Finally, the mechanism of suppressing the formation of intermetallic compounds by RTA is discussed. Our work extends the preparation window for high-quality Ge1-xMnx FMS, and also provides a promising choice for further investigation of ferromagnetic semiconductors.

Accession Number: WOS:001172879000002

ISSN: 2469-9950

eISSN: 2469-9969