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Raman scattering and magnetizations studies of (Al, Cr)-codoped 4H-SiC |
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| Authors: | B Song XL ChenJC Han G WangHQ Bao LB DuanKX Zhu H Li ZH ZhangWY Wang WJ WangXH Zhang SH Meng |
| Institution: | a Research Station on Material Science and Engineering for Postdoctoral Fellows, Harbin Institute of Technology, Harbin 150080, China b Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150080, China c Research and Development Center for Functional Crystals, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China d Department of Physics, Northwestern Polytechnical University, 710072, China e College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China f Center for Composite Materials, Harbin Institute of Technology, Harbin 150080, China g Liaoning Key Materials Laboratory for Railway, School of Materials Science and Engineering, Dalian Jiaotong University, Dalian, 116028, China |
| Abstract: | In this study, the insertion of both Al and Cr atoms into SiC matrix has been experimentally evidenced by X-ray diffraction, Raman scattering, elements analysis and magnetic measurements. Structure analysis showed that (Al, Cr)-codoped SiC has a single-phase 4H-crystal structure and no trace of any other impurity phases were detected. Raman scattering showed that several new features appeared in (Al, Cr)-codoped 4H-SiC: (1) the vanishing of the folded longitudinal-optical phonons modes-plasmon coupling (FLOPC) modes with x=(q/qB)=0; (2) an obvious absorbing peak was found in Si1−x−yAlxCryC with y=0.0203 at%; (3) folded transverse-optical (FTO) mode shifts to high frequency and linewidths full widths at half maximum (FWHM)] decrease with increase in Cr content. Magnetic properties characterizations showed that weak ferromagnetism order is established. With increase in Cr content, the magnetization decreased. No clear influence of Al doping on the magnetic properties of codoped 4H-SiC is evidenced while the magnetic origin should be ascribed to be induced by Cr. It is speculated that doping Cr elements at Si sites destroy the effective coupling of the spins induced by Al doping. The major role of Al is to stabilize the codoped crystal structure as 4H-single-phase. |
| Keywords: | Ferromagnetic SiC Codoped |
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