La_(0.8)Sr_(0.2)Co_(1-x)Fe_xO_3材料局域结构的研究  

LOCAL STRUCTURE FEATURES OF La_(0.8)Sr_(0.2)Co_(1-x)Fe_xO_3 BY EXAFS

作　　者：吴成国[1] 武文远[1] 龚艳春[1] 杜华月[1] 陈蓉[1] 

机构地区：[1]解放军理工大学理学院,南京210011

出　　处：《低温物理学报》2011年第4期313-316,共4页Low Temperature Physical Letters

摘　　要：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Co3+-O、Co4+-O、Fe3+-O和Fe4+-O键,Co3+-O键和Fe3+-O键长几乎相等,Co4+-O键和Fe4+-O键长几乎相等,但是Co3+-O、Fe3+-O键长与Co4+-O、Fe4+-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.

关 键 词：EXAFS 劈裂 局域结构 溶胶-凝胶 

分 类 号：O469[理学—凝聚态物理]