ErFeO_3单晶反常负磁化和补偿温度点性研究  

NOVEL NEGATIVE MAGNETIZATION IN PEROVSKITE ERFEO_3 SINGLE CRYSTAL

作　　者：詹晟[1] 曹世勋[1] 袁淑娟[1] 鲁波[2] 张金仓[1] 

机构地区：[1]上海大学物理系,上海200444 [2]上海大学微结构重点实验室

出　　处：《低温物理学报》2012年第5期337-341,共5页Low Temperature Physical Letters

基　　金：国家自然科学基金重点项目(批准号:50932003;11074163);教育部高等学校博士学科点专项科研基金(批准号:20093108120006);上海市教育委员会科研创新项目(批准号:12YZ018)资助的课题~~

摘　　要：通过光学浮区法生长了直径为6mm,长度约为75mm的晶体,结构分析表明实验样品呈单相的正交钙钛矿结构,并通过劳厄定向仪对ErFeO3晶体进行了定向.系统测量了ErFeO3晶体a,c方向的热磁曲线和不同温度下的磁化曲线.结果表明,随着温度的降低,在98～86K范围该体系经历了从Г4(Gx,Fz)相到Г2(Gz,Fx)相的自旋重取向转变.在ErFeO3体系中,由于Er离子磁矩反平行于Fe离子磁矩分子场,在46K附近,在a方向上Er的反向磁矩大于Fe离子磁矩,导致出现负磁化和磁化补偿点现象.随着外加测量场的增强,a轴向上的负磁化被抑制,补偿温度点向高温移动.The ErFeOa single crystal rod of approximately 6 mm in diameter and 75 mm in length was grown using the floating zone technique. Structure analysis shows that the sample has orthorhombic perovskite structure, and a, c directions of ErFeO3 single crystal are determined by the Laue method. M-T curves along a, c direction and magnetic hysteresis loops on different temperatures are studied. The results show that ErFeO3 magnetic system goes through transition from Г4 （Gx ,Fx） phase toГ2 （Gx ,Fx） phase with the decreasing of temperature from 98 to 87 K. Near 46 K, the M-T curve along a axis shows the negative magnetization which can be attributed to the effect of Er ions whose magnetic moments direction aligned opposite to the canted Fe moments. The negative magnetization phenomenon is suppressed in higher magnetic field because the magnetic moments of Er ions can not antiparallel to the external magnetic field completely, and the compensation point shifts to higher temperature.

关 键 词：ErFeO3晶体 光学浮区法 负磁化 

分 类 号：O74[理学—晶体学]