Dy_(0.9)Sm_(0.1)FeO_3单晶中的自旋组态和磁化翻转效应  

SPIN CONFIGURATION AND MAGNETIZATION REVERSAL IN Dy_(0.9)Sm_(0.1)FeO_3 SINGLE CRYSTAL

作　　者：陈蕾[1,2] 赵伟尧[1] 曹世勋[1,3,4] 郑仁奎[2] 康保娟[1] 张金仓[3,4] 

机构地区：[1]上海大学物理系,上海200444 [2]中国科学院上海硅酸盐研究所,上海200050 [3]上海大学材料基因组工程研究院,上海200444 [4]上海市高温超导重点实验室,上海200444

出　　处：《低温物理学报》2016年第2期161-166,共6页Low Temperature Physical Letters

基　　金：得到国家自然科学基金项目(批准号:51372149;11274221;1574194)资助的课题~~

摘　　要：我们用光学浮区法生长了稀土正铁氧体Dy_(0.9)Sm_(0.1)FeO_3(DSFO)单晶,并通过劳厄衍射法确定了单晶样品的方向.对DSFO单晶的磁性研究表明:在DyFeO_3中掺杂10%的Sm后,体系的自旋重取向转变温度从51 K(DyFeO_3)降低到9 K,而且相变过程变成了由Γ_4到Γ_(42)再到Γ_1.在12—300 K区间DSFO处于Γ_4组态,沿c方向Fe离子磁晶格有一个净的磁矩和一个由它诱导的稀土离子的净磁矩.稀土磁矩和Fe磁矩之间本征地反平行耦合,但一个较小的磁场可以改变反平行耦合到平行耦合.在场冷降温模式下的磁化-温度曲线测试中,我们发现在不同的磁场下磁化曲线会在不同的位置发生跳变;这一现象由稀土磁矩和Fe磁矩之间的平行反平行转变导致,有望作为特定条件下的自旋开关而应用于自旋电子学器件中.We report the spin configuration and magnetization reversal in a Dy0. 9 Sm0.1FeO3 （DSFO） orthoferrite single crystal which is grown by the Optical-Floating-Zone method. The Laue camera is conducted to orient the single crystal. We employe a Superconduct Quantum Interfere Device （SQUID） to perform the magnetic characterization and find that： 1） the apparance of Sm would decrease the interaction between Dy-Fe, which thus decreases the spin reorientation temperature from 51 K （for DyFeO3 ） to about 9 K （for DSFO）; 2） the spin reorientation type is verified to be Г4 Г42 to Г1, exhibiting another effect of Sm doping; 3 ） the canted antiferromagnetic Fe sublattice contributes to a weak ferromagnetic component FFe, which could also induce a rare- earth-ions weak ferromagnetic component FR below about 200 K. FFe and FR desire to be antiparallel to each other,but possess a quite small energy difference from parallel coupling state. Thus, the small applied field would keep the weak ferromagnetic components parallel, as a metastable state, in the cooling process, until a certain point where a jumping occurs and FR flips to the opposite direction. The study would lead to a better understanding of spin reorientations in rare-earth orthoferrites, as well as precisely predict the jumping in field cooling magnetization curves, which will lead to the exploring in spin switching area.

关 键 词：稀土铁氧化物 自旋组态 自旋电子学 

分 类 号：O469[理学—凝聚态物理]