Co掺杂钙钛矿SrTiO_3磁性机理的理论研究  

Theoretical Study on the Magnetic Mechanism of Co-doped Perovskite SrTiO_3

作　　者：王青[1] 李强[1] 戴剑锋[1] 郭永庆[1] 张仁辉[1] 

机构地区：[1]兰州理工大学理学院,兰州730050

出　　处：《材料导报》2011年第4期1-4,共4页Materials Reports

基　　金：国家自然基金项目(50873047);甘肃省教育厅基金项目(0903-12)

摘　　要：采用第一性原理LDA+U方法研究了Co掺杂SrTiO3的磁性机理,对不同掺杂体系的基态能量、电子结构、态密度、居里温度及缺陷替位能进行了计算分析。结果表明,无氧空位的掺杂体系呈现出反铁磁性或顺磁性,而有氧空位掺杂体系却表现出铁磁性;掺杂体系的晶胞磁矩主要来自于Co离子局域磁矩的贡献;随着Co和氧空位浓度的增加,掺杂体系表现出室温铁磁性;Co离子和氧空位的共同作用降低了体系的缺陷替位能;掺杂体系中Co离子之间的铁磁性耦合可以用束缚磁极子机制解释。The magnetic mechanism in Co, doped perovskite SrTiO3 with and without oxygenvacancies was investigated by first principles with LDA＋U approach. Ground state energy, electronic structures, density of states, Curie temperature and substitution energy were investigated for various configurations. The calculated results imply that the species without oxygen vacancies exhibit antiferromagnetism or paramagnetism. The species with oxygen vacancies show strong ferromagnetism. Unit cell magnetic moment originates from local magnetic moment of Co ions. With the increasing concentration of Co ions, room-temperature ferromagnetism can be realized. The interaction between Co ions and oxygen vacancies will lower the defect substitution energy of Co-doped SrTiO3. The ferromagnetic coupling between Co ions can be explained in the terms of the bound magnetic polaron mechanism.

关 键 词：CO SRTIO3 磁性 第一性原理 

分 类 号：O482.5[理学—固体物理]