標題: Defect induced ferromagnetic ordering in epitaxial Zn0.95Mn0.05O films on sapphire (0001)
作者: Liu, Wei-Rein
Pao, Chih-Wen
Yu, Doris Weijyun
Chin, Yi-Ying
Wu, Wen-Bin
Lin, Hong-Ji
Haw, Shu-Chih
Chu, Chia-Hung
Chao, Tzu-Yang
Hsu, Hsu-Cheng
Chen, Jin-Ming
Hsu, Chia-Hung
Hsieh, Wen-Feng
Chen, Chien-Te
電子物理學系
光電工程學系
光電工程研究所
Department of Electrophysics
Department of Photonics
Institute of EO Enginerring
關鍵字: room temperature ferromagnetism;epitaxial thin films;bound magnetic polaron;Mn-doped ZnO;vacancy induced
公開日期: 4-Dec-2019
摘要: We report the influence of Mn dopant on magnetic properties of Zn0.95Mn0.05O (ZMO)/Al2O3(0001) hetero-epitaxial systems grown by using pulsed-laser deposition. The room temperature (RT) intrinsic ferromagnetic (FM) ordering verified by superconducting quantum interference device magnetometer and x-ray magnetic circular dichroism spectrum of Mn L-2(,3) edges is ascribed to the substitutional Mn atoms in the Zn site of ZnO. Mn in ZMO has a tetrahedral local symmetry instead of the octahedral symmetry of MnO, after verifying the absence of the Mn-related impurities or clusters in ZMO epitaxial film by Mn K-edge and Zn K-edge x-ray absorption spectroscopy spectrum, as well as the analysis of long-range structural ordering on Renninger scan of forbidden (0005) reflection in x-ray diffraction, transmission electron microscopy and Raman spectrum. Comparison of x-ray absorption spectra of ZMO with those of ZnO epilayers at O K-, Zn K-, and L-3-edges indicates that the substitution of the Zn site with Mn enhances the charge-transfer (CT) transition and the presence of Zn vacancies (V-Zn) also dominate the photoluminescence (PL) spectrum, implying that the formation of numerous V-Zn defects plays an important role in activating FM interactions. The strong CT effect and the existence of high-density V-Zn suggest that the intrinsic RT FM ordering of insulating ZMO is a result of the formation of the bound magnetic polarons (BMPs) that interact with each other via intermediate magnetic impurities.
URI: http://dx.doi.org/10.1088/1361-648X/ab3b71
http://hdl.handle.net/11536/152890
ISSN: 0953-8984
DOI: 10.1088/1361-648X/ab3b71
期刊: JOURNAL OF PHYSICS-CONDENSED MATTER
Volume: 31
Issue: 48
起始頁: 0
結束頁: 0
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