稀土(Sm，Gd，Dy)代换镧对La0．7Sr0．3MnO3磁电性质的影响及室温CMR的增强  

Influence of Rare Earths(Sm,Gd,Dy) Substitution for Lanthanum on Magnetic and Electric Properties La_(0.7)Sr_(0.3)MnO_3 and Strengthening Effect on Room-Temperature CMR

作　　者：宋启祥[1] 彭振生[1,2] 严国清[1] 毛强[1] 王闻琦[1] 

机构地区：[1]宿州学院自旋电子与纳米材料安徽省重点实验室,安徽宿州234000 [2]中国科学技术大学结构分析重点实验室,安徽合肥230026

出　　处：《中国稀土学报》2008年第5期640-646,共7页Journal of the Chinese Society of Rare Earths

基　　金：国家自然科学基金重点项目(19934003);安徽省教育厅自然科学研究重大项目(ZD2007003-1);安徽省高等学校自然科学研究项目(KJ2008A19ZC);宿州学院教授(博士)科研启动基金项目(2006jb02)

摘　　要：用固相反应法制备了La0.7-xSmxSr0.3MnO3,La0.7-xGdxSr0.3MnO3和La0.7-xDyxSr0.3MnO3(x=0.00,0.10,0.20,0.30)系列样品。通过M-T曲线,ρ-T曲线,研究了用稀土离子代换La对La0.7Sr0.3MnO3磁电性质和磁电阻的影响。结果表明:稀土离子代换La引起的晶格畸变和稀土离子的额外磁性对钙钛矿锰氧化物的磁电性质影响很大;稀土离子代换La是改变钙钛矿锰氧化物居里温度和增强MR的有效途径;适量稀土离子代换La可以在室温附近产生大的磁电阻。A series of samples La0.7-xSmxSr0.3MnO3, La0.7-x Gd, Sr0.3 MnO3 and La0.7-x DyxSr0.3 MnO3 （ x = 0.00, 0.10, 0.20, 0.30） were prepared by solidstate reaction. The influence of rare-earth ions substitution for La on magnetic and electric properties and on magnetoresistance （MR） was studied through the measurements of M-T curves and ρ-T curves. The results showed that the lattice distortion induced by therare-earth ions substitution for La and extra magnetism of the rare-earth ions had great influence on magnetic and electric properties of perovskite manganite. And the rare-earth ions substitution for La was an effective way to change Curie temperature and to strengthen MR in perovskite manganite; and an appropriate doping proportion would generate a large MR near room temperature.

关 键 词：磁电性质 庞磁电阻 居里温度 稀土离子代换镧 钙钛矿锰氧化物 稀土 

分 类 号：O482.54[一般工业技术—材料科学与工程]