反铁磁半金属GdSb中极大磁电阻效应研究  

A Study of Colossal Magnetoresistance Effect in the Antiferromagnetic Semimetal GdSb

作　　者：宋金军 唐昉 周苇 房勇[1] 于海林[1] 韩志达[1] 钱斌[1] 江学范[1] SONG Jinjun;TANG Fang;ZHOU Wei;FANG Yong;YU Hailin;HAN Zhida;QIAN Bin;JIANG Xuefan(School of Physics and Electronic Engineering,Changshu Institute of Technology,Changshu 215500,China)

机构地区：[1]常熟理工学院物理与电子工程学院,江苏常熟215500

出　　处：《常熟理工学院学报》2018年第5期1-4,共4页Journal of Changshu Institute of Technology

摘　　要：具有极大磁电阻的半金属材料因其可能具有非寻常的拓扑电子结构、电输运特性,可为高能物理相关的狄拉克费米子、外尔费米子以及马约拉纳费米子的研究提供崭新的舞台,受到了广泛关注.本文通过助溶剂法合成高质量的GdSb单晶并系统地研究其结构、磁性、电输运等性质,发现该材料具有NaCl型晶体结构(空间群Fm-3m),并且在23.4 K附近经历反铁磁相变.电输运结果表明GdSb具有金属导电性,自旋无序效应可导致磁相变温度附近的电阻出现异常.更吸引人的是,样品在磁场(H=9 T)作用下,低温(2 K)电阻将出现平台,展示出极大的磁电阻效应(MR=12 100%).通过霍尔效应及第一性原理计算,发现GdSb是多带及补偿型半金属,其中电子与空穴的数目相当.电子-空穴补偿及较大的载流子迁移率是极大磁电阻的来源.Semimetals with colossal magnetoresistance have attracted a significant interest because of not only their possible nontrivial electronic structures,and unusual transport properties,but also the deep connections to the high-energy physics.The authors of this paper synthesize the GdSb single crystal and systematically characterize its crystal structure,magnetism,and electric transport properties.It is found that this compound crystallizes in NaCl-type structure with a space group Fm-3m,and experiences antiferromagnetic phase transition at 23.4 K.Electric transport measurement reveals that the compound is metallic,in which spin disorders induce a resistivity anomaly emerging around its magnetic transition temperature.Intriguingly,obvious resistivity plateaus are observed at a low temperature,when the compound is subjected to the external magnetic field,showing colossal magnetoresistance effect up to 12 100%at 2 K and 9 T.Through Hall resistivity measurement and first-principles band structure calculations,GdSb is believed to be a multiband and compensated semimetal,in which the total carrier concentrations of electrons and holes are almost comparable.The electron-hole compensation and ultrahigh mobility of GdSb can be attributed to the colossal magnetoresistance in this compound.

关 键 词：反铁磁 磁电阻 半金属 

分 类 号：O469[理学—凝聚态物理]