摘要
目的:本工作利用分析电子显微术和X 射线衍射方法研究了Ti0 93Co0 07O2薄膜材料的显微结构。研究结果表明:Co元素主要以替代TiO2锐钛矿结构中的Ti的形式存在;虽然利用透射电镜观察,可偶尔看到局部Co的金属团簇的存在,但数量极少。这表明Ti0 93Co0 07O2薄膜具有独特的稀磁系统特征,其铁磁性的产生不来自于Co的团簇,而可能来自载流子调制。通过X 射线能谱分析得到了Ti0 93Co0 07O2薄膜中Co与Ti的成分分布,Co与Ti的原子比不严格地等同于薄膜的名义配比0 07,而是在纳米尺度上有成分起伏。高分辨图像显示,Ti0 93Co0 07O2薄膜中晶面扭曲,晶格发生畸变,主要是由于薄膜中Co的成分起伏、价态变化等因素共同造成的。
In this study, the microstructure of Ti_(0.93)Co_(0.07)O_2 film has been investigated by analytical electron microscopy. The results showed that the Co-TiO_2 (anatase) is solid-solution and the sites of a part of Ti atoms were replaced by Co atoms, Co cluster was occasionally observed. It strongly supports that the Co-TiO_2 (anatase) has the characteristic of an intrinsic diluted magnetic system and its ferromagnetism results from probably a carrier mediated mechanism, but not from Co clusters. The distributions of Co in TiO_2 anatase were determined by X-ray energy dispersive spectra microanalysis. The Co/Ti atomic ratio is not as the stoichiometric ratio 0.07 but existing a compositional fluctuation throughout the film in nanometer scale. High-resolution lattice images displayed the disordered regions and the distorted atomic planes in the film, which is thought to be mostly caused by the compositional fluctuation and valence state variation of cobalt elements in the film.
出处
《电子显微学报》
CAS
CSCD
北大核心
2004年第6期603-608,共6页
Journal of Chinese Electron Microscopy Society
基金
国家自然科学基金资助项目
国家973项目支持.
