中国物理B ›› 2013, Vol. 22 ›› Issue (3): 37504-037504.doi: 10.1088/1674-1056/22/3/037504

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Defect types and room-temperature ferromagnetism in undoped rutile TiO2 single crystals

李东翔a b, 秦秀波c, 郑黎荣d, 李玉晓b, 曹兴忠a, 李卓昕a, 杨静a, 王宝义a   

  1. a Key Laboratory of Nuclear Analysis Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China;
    b School of Physical Engineering, Zhengzhou University, Zhengzhou 450001, China;
    c Research Center for Application of Nuclear Technology, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China;
    d Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
  • 收稿日期:2012-09-05 修回日期:2012-10-25 出版日期:2013-02-01 发布日期:2013-02-01
  • 基金资助:
    Project supported by the Young Scientists Fund of the National Natural Science Foundation of China (Grant No. 61006066) and the National Natural Science Foundation of China (Grant No. 11175191).

Defect types and room-temperature ferromagnetism in undoped rutile TiO2 single crystals

Li Dong-Xiang (李东翔)a b, Qin Xiu-Bo (秦秀波)c, Zheng Li-Rong (郑黎荣)d, Li Yu-Xiao (李玉晓)b, Cao Xing-Zhong (曹兴忠)a, Li Zhuo-Xin (李卓昕)a, Yang Jing (杨静)a, Wang Bao-Yi (王宝义)a   

  1. a Key Laboratory of Nuclear Analysis Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China;
    b School of Physical Engineering, Zhengzhou University, Zhengzhou 450001, China;
    c Research Center for Application of Nuclear Technology, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China;
    d Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
  • Received:2012-09-05 Revised:2012-10-25 Online:2013-02-01 Published:2013-02-01
  • Contact: Qin Xiu-Bo E-mail:qinxb@ihep.ac.cn
  • Supported by:
    Project supported by the Young Scientists Fund of the National Natural Science Foundation of China (Grant No. 61006066) and the National Natural Science Foundation of China (Grant No. 11175191).

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摘要： Room-temperature ferromagnetism has been experimentally observed in annealed rutile TiO2 single crystals when magnetic field is applied parallel to the sample plane. By combining X-ray absorption near edge structure spectrum and positron annihilation lifetime spectroscopy, Ti3+-VO defect complexes (or clusters) have been identified in annealed crystals at high vacuum. We elucidate that the unpaired 3d electrons in Ti3+ ions provide the observed room-temperature ferromagnetism. Besides, excess oxygen ions in TiO2 lattice could induce a number of Ti vacancies which increase magnetic moments obviously.

关键词: annealing, oxygen vacancies, Ti3+-VO defect complexes, ferromagnetism

Abstract: Room-temperature ferromagnetism has been experimentally observed in annealed rutile TiO2 single crystals when magnetic field is applied parallel to the sample plane. By combining X-ray absorption near edge structure spectrum and positron annihilation lifetime spectroscopy, Ti3+–VO defect complexes (or clusters) have been identified in annealed crystals at high vacuum. We elucidate that the unpaired 3d electrons in Ti3+ ions provide the observed room-temperature ferromagnetism. Besides, excess oxygen ions in TiO2 lattice could induce a number of Ti vacancies which increase magnetic moments obviously.

Key words: annealing, oxygen vacancies, Ti3+–VO defect complexes, ferromagnetism

中图分类号:  (Magnetic semiconductors)

  • 75.50.Pp
71.55.-i (Impurity and defect levels) 75.20.Hr (Local moment in compounds and alloys; Kondo effect, valence fluctuations, heavy fermions)