材料期刊网

采用溶胶-凝胶法制备了La0.8Sr0.2Co1-xFexO3样品,并测量了各样品的X射线衍射谱（XRD）和X射线吸收精细结构（XAFS）谱。XRD分析研究发现Fe的掺杂引起了La0.8Sr0.2CoO3材料相分离;在前期对X射线吸收精细结构谱近边分析的基础上,进一步分析扩展边X射线吸收精细结构谱,表明在La0.8Sr0.2Co1-xFexO3材料中存在Co^3＋-O、Co^4＋-O、Fe^3＋-O和Fe^4＋-O键,Co^3＋-O键和Fe^3＋-O键长几乎相等,Co^4＋-O键和Fe^4＋-O键长几乎相等,但是Co^3＋-O、Fe^3＋-O键长与Co^4＋-O、Fe^4＋-O键长不相等,在晶体中形成不同离子的富集区,因此在晶体中构成了两种相结构.

The local structures around Co and Fe ions in La0.8Sr0.2Co1-xFexO3 prepared by sol-gel method were investigated by XAFS.XRD shows that in La0.8Sr0.2Co1-xFexO3 samples has almost all of the diffraction peaks are splitted,implying that there are probably two different crystal structures in Fe-doped La0.8Sr0.2CoO3 samples.The results of EXAFS indicate that there are four bands such as Co^3＋-O、Co^4＋-O、Fe^3＋-O and Fe^4＋-O bands in La0.8Sr0.2Co1-xFexO3 samples,Co^3＋-O band and Fe^3＋-O band have almost length,Co^4＋-O band and Fe^4＋-O land have almost length,but the length of the four bands are not equal,thus these results induce two different crystal structures in Fe-doped La0.8Sr0.2CoO3 samples.