(La1-xEux)2／3Sr1／3MnO3室温低场磁电阻效应  

Low-magnetic field and room temperature magnetoresistance effects of (La_(1-x)Eu_x)_(2/3)Sr_(1/3)MnO_3

作　　者：徐美华[1,2] 胡秀坤[3] 张世远[2] 

机构地区：[1]南京工业大学理学院,江苏南京210009 [2]南京大学固体微结构重点实验室,江苏南京210093 [3]中国计量学院材料科学与工程学院,浙江杭州310018

出　　处：《南京工业大学学报（自然科学版）》2008年第6期23-26,共4页Journal of Nanjing Tech University(Natural Science Edition)

基　　金：国家重点基础研究发展规划(973计划)资助项目(2001CB610603)

摘　　要：采用溶胶-凝胶法,以半径较小的Eu3+部分替代离子半径较大的La3+,制备一系列(La1-xEux)2/3Sr1/3MnO3大块多晶试样(x=0.1、0.2、0.3、0.4、0.5、0.6、0.7),对试样进行X射线衍射表征,分析Eu掺入量对试样晶体结构的影响.测量试样居里温度、电阻率、室温低场磁电阻等电磁行为.结果表明:随着Eu掺入量的增大,A位的平均离子半径减小,试样居里温度降低,电阻率升高,x=0.2试样在室温低场(H=0.87 T)下磁电阻达到-6.53%.室温低场磁滞回线显示Eu掺入量增加,比饱和磁化强度反而降低.By substitution of Eu^3＋ with smaller ionic radius for La^3＋ with larger one, a series of bulk polycrystalline （La1-xEux）2/3Sr1/3MnO3 （x = 0. 1,0.2, 0. 3, 0. 4, 0. 5, 0. 6 and 0.7） samples were prepared by sol-gel method. The influence of x on the structures was analyzed by X-ray diffraction （XRD）. Their Curie temperature, the resistivity and magnetoresistances were studied. Results indicate that with the increasing of x, the Curie temperature of the samples decreases and the resistivity increases. MR is -6. 53% for x =0. 2 sample at the room temperature and 0. 87 T magnetic field, m-H hysteresis loop at the room temperature indicates that with increasing of doping concen- tration of Eu magnetization the saturated magnetization value decreases.

关 键 词：钙钛矿锰氧化物 磁电阻 相分离 溶胶凝胶法 

分 类 号：O482.5[理学—固体物理] TM273[理学—物理]