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无机材料学报

无机材料学报

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复合氧化物Ln0.67Sr0.33MnO_3(Ln=La、Pr、Nd、Sm)的制备、结构与电性

李亚栋1,3; 章建辉1; 朱长飞2; 刘卫2; 周移1; 钱逸泰1,3   

  1. 1.中国科学技术大学应用化学系; 合肥230026; 2中国科学技术大学内耗与固缺陷体开放实验室 合肥 230026; 3. 中国科学技术大学结构成分开放实验室 合肥 230026
  • 收稿日期:1996-10-07 修回日期:1996-11-20 出版日期:1997-10-20 网络出版日期:1997-10-20

Preparation, Structure and Electrical Properties of Ln0.67Sr0.33MnO3(Ln=La, Pr, Nd, Sm)

LI Yadong1,3; ZHANG Jianhui1; ZHU Changfei2; LIU Wei2; ZHOU Yi1; QIAN Yitai1,3   

  1. 1.Department of Applied Chemistry of University of Science and Technology of ChinaHefei 230026 China; 2.Labortory of Interner Friction and Defects in Solid Academia Sinica Hefei 230026 China; 3. Structure Resaearch Laborary, Academia Sinica Hefei 230026 China
  • Received:1996-10-07 Revised:1996-11-20 Published:1997-10-20 Online:1997-10-20

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摘要： 本文通过共沉淀工艺会成了复合氧化物Ln0.67Sr0.33MnO3(Ln=La、Pr、Nd、Sm）与传统陶瓷制各方法相比，成相温度降低约450℃．经X射线衍射分析表明，所得复合氧化物为立方钙钛矿结构，晶胞参数随稀土离子半径变化而呈规律性变化．样品的四极法电阻率测试结果表明：样品中的稀土离子Ln的离子半径对其本身的导电性起决定性的作用．应用双交换理论，只能部分地解释该实验结果．由此推测稀土离子中的4f层电子在电导过程中起一定作用．

关键词: 共沉淀工艺, 钙钛矿结构, 离子半径, 导电性

Abstract: The complex oxide compounds Ln0.67Sr0.33MnO3(Ln=La, Pr?, Nd, Sm) were synthesized through co-precipitation route. Compared with the
traditional ceramic sintering method, the temperature at which the compounds were formed were reduced by about 450℃. The X-ray powder diffraction patterns indicated that the structure of the compounds belongs to cubic perovskite-type phase and their crystal
unit parameters vary with the radius of rare earth ions regularly. The resistivity of samples was measured by a standard four-probe method. The results show that the radius of rare
earth ion is crucial to the ability of electric conduction of the compounds. The double exchange theory can only explain our experimental results partially. The autors deduced that the
electrons of 4f state of rare earth ions may play a role in electric conduction.

Key words: co-precipitation, perovskite-type phase, ion radius, electric conduction