A位阳离子无序对La_(2/3)Ca_(1/3)MnO_3结构和输运性能的影响  

Effects of A-site Cation Disorder on Structural and Transport Properties of La_(2/3)Ca_(1/3)MnO_3

作　　者：张亚梅[1] 王智河[2] 吴小山[2] 张兵[1] 

机构地区：[1]江苏科技大学物理系,镇江212003 [2]南京大学固体微结构国家重点实验室,南京210093

出　　处：《材料导报》2012年第8期29-32,共4页Materials Reports

基　　金：江苏科技大学博士科研启动基金

摘　　要：利用固相反应法合成了(La1-xDyx)2/3Ca1/3MnO3(x=0、0.1、0.2)材料,研究阳离子无序对微结构和电输运性能的影响。Rietveld方法拟合XRD结果表明,随着Dy掺杂浓度的增加,晶胞参数和Mn-O键长键角发生了明显的变化,造成MnO6八面体畸变。电输运性能显示:样品电导率随Dy掺杂量的增加而减小,其导电机制符合半导体小极化子模型。Dy掺杂浓度的增加使得钙钛矿ABO3的A位阳离子无序度增加,影响了样品的微结构;A位无序效应增强了载流子的晶格散射,抑制了电导率。（La1-r Dyx ）2/3 Ca1/3 MnO3 （x= 0, 0. 1, 0. 2） materials were successfully fabricated by solid state reaction. The effects of the cation disorder on the microstructure and electrical transport properties were investigated. The results from XRD and Rietveld refinement indicate that unit cell parameters and Mn-O bond distances and angles are distinctly varied with Dy doping content increase and MnO6 octahedra is distorted. The electrical transport properties show that the electrical conductivity decreases with Dy doping content increase and the electrical conductivity of all the samples is found to obey the small polaron hopping mechanism. Dy doping increases A-site cation disorder and affects the microstructure of all the samples. A-site cation disorder enhances the carrier scattering in the lattice and controis the electrical conductivity.

关 键 词：电导率 RIETVELD方法 无序 小极化子模型 

分 类 号：O469[理学—凝聚态物理] TB321[理学—电子物理学]