La_(0.7-x)Dy_xSr_(0.3)MnO_3体系低温磁行为和电阻率的反常  

ABNORMALITY OF MAGNETIC BEHAVIOUR AND RESISTIVITY AT LOW TEMPERATURE IN La_(0.7-x)Dy_xSr_(0.3)MnO_3 SYSTEM

作　　者：刘宁[1] 严国清[1] 徐素军[2] 童伟[2] 

机构地区：[1]宿州学院物理系,安徽宿州234000 [2]中国科学技术大学结构分析开放实验室,合肥230026

出　　处：《硅酸盐学报》2005年第4期433-437,共5页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金重点项目(19934003);"973"计划(001CB610604)资助项目。

摘　　要：通过测量样品的磁化强度温度(M T)曲线、电阻率温度(ρT)曲线及磁电阻温度(MR T)曲线,研究了Dy掺杂(0.00≤x≤0.30)对La0.7-xDyxSr0.3MnO3体系磁电性质的影响。实验发现:随Dy掺杂量的增加,体系的磁结构从长程铁磁有序向自旋团簇玻璃态、反铁磁状态转变。x为0.20,0.30时的低温磁行为发生异常,电行为存在低温电阻率极小值的现象。这些现象不仅来源于掺杂引起的晶格效应,而且来源于掺杂引起的额外磁性耦合。Influence of Dy dosage (0.00&lex&le0.30) on magnetic and electric properties of La0.7-xDyxSr0.3MnO3 were studied by measuring M-T (magnetization-temperature), ρ-T (resistivity-temperature) and MR-T (magnetoresistance-temperature) curves of samples under different temperatures. Experimental results show that with increasing Dy dosage, the system undergoes a transition from long range ferromagnetic order to the cluster-spin glass state and further to anti ferromagnetic order. For samples of x=0.20 and x=0.30, magnetic behavior is abnormal at low temperature, and electric behavior shows the phenomenon that resistivity at low temperature has minimum value. These phenomena not only come from lattice effect induced by doping, but also come from extra magnetic coupling induced by doping.

关 键 词：锰氧化物 低温电阻率反常 晶格效应 额外磁性耦合 

分 类 号：O482.54[一般工业技术—材料科学与工程]