Nb^(5+)的低温掺杂对La_(0.67)Sr_(0.33)MnO_3结构、磁性和电性的影响  

The Influence of Nb^(5+)Doping on the Structure,Magnetic and Electric Properties of La_(0.67)Sr_(0.33)MnO_3 Sintered at Low Temperature

作　　者：黄宝歆[1] 

机构地区：[1]潍坊学院,山东潍坊261061

出　　处：《潍坊学院学报》2008年第4期94-96,共3页Journal of Weifang University

基　　金：国家重点基础研究专项经费资助项目(No.G1998061310);潍坊学院自然科学基金(2007Z01)

摘　　要：将 Nb_2O_5掺杂到用溶胶一凝胶法制备的 La_(0.67)Sr_(0.33)MnO_3(LSMO)微粉中,XRD 结果表明:随掺杂量的增多,样品中出现相分离,其一为具有菱方结构的钙钛矿材料,另一相为 LaNbO_4。随 Nb 掺入量的增多,T_P 单调下降而 T_C 没有明显变化,说明低温烧结减弱了 B 位替代效应。在 x=0.07的样品中得到最大电阻率为23.7 Ωcm,比 LSMO 高三个数量级,这主要是尺寸效应所决定。The samples were prepared by doping Nb2O5 into the La0.67 Sr0.33 MnO3 powder, which is synthesized by the sol--gel method. The XRD analysis shows that there exist two phases in the samples with larger Nb addition. One can be indexed as rhombohedral perovskite structure and another is corresponding to the LaNbO4 peaks. With increasing Nb addition, Tp decreases monotonically while Tc remains almost the same, showing the less substitute effect on the B sites due to the lower sintered temperature. There is a maximum resistivity p as large as 23.7 Ωcm （ 281 K） for the sample with x= 0.07, which is higher than that for LSMO （0.021Ωcm at 372 K） by three orders of magnitude. It is mainly due to the ionic size effect.

关 键 词：稀土掺杂锰氧化物 颗粒体系 两相复合系统 

分 类 号：O482.5[理学—固体物理]