Defect types and room-temperature ferromagnetism in undoped rutile TiO_2 single crystals

• 作 者: 李东翔 秦秀波 郑黎荣 李玉晓 曹兴忠 李卓昕 杨静 王宝义
• 机 构: Key Laboratory of Nuclear Analysis Techniques,Institute of High Energy Physics,Chinese Academy of Sc
• 出 处: Chinese Physics B
• 发表日期: 2013年03期
• 关键词: rutile annealed elucidate complexes lifetime annealing magnetism Room anatase ma

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

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