类铁基超导材料BaMn2Bi2电输运性质的各向异性  

Anisotropy of the Electrical Transport Properties about Iron-based Superconductor Analogue BaMn2Bi2

作　　者：张慧亭 傅瑜[1] 张萍[1] 何俊宝 ZHANG Hui-ting;FU Yu;ZHANG Ping;HE Jun-bao(College of Physics and Electronic Engineering,Nanyang Normal University,Nanyang 473061,China)

机构地区：[1]南阳师范学院物理与电子工程学院

出　　处：《人工晶体学报》2019年第9期1631-1635,共5页Journal of Synthetic Crystals

基　　金：国家自然科学基金(11404175);河南省自然科学基金(182300410274);南阳市科技发展计划(JCQY2018015);南阳师范学院青年项目;南阳师范学院实验(实训)室开放项目

摘　　要：层状过渡金属化合物BaMn2Bi2与“122”型铁基超导材料BaFe2As2具有十分相似的特征,不仅具有相同的四方ThCr2Si2晶体结构,而且都是反铁磁基态。我们采用助溶剂法制备了BaMn2Bi2的高质量大尺寸单晶样品,通过X射线衍射、能谱分析系统、综合物性测量系统表征了该单晶样品的晶体结构、化学成分和电输运性质,并对其电输运性质的各向异性进行了系统的研究。研究发现:零磁场下BaMn 2Bi 2的面内电阻率和面间电阻率从300 K到100 K随温度下降而下降,表现出坏金属行为;但是100 K以下随温度下降而上升,表现出半导体行为,其激发能约为2.5~3 meV。施加9 T磁场后,100 K以上两个方向的磁阻仅为5%左右,而100 K以下两个方向磁阻都逐渐下降,直到1.8 K达到-18%左右。无论是否施加磁场,BaMn2Bi2的面内电阻率和面间电阻率都没有表现出明显的各向异性。BaMn2Bi2 is a layered transitional metal compound with a tetragonal ThCr2Si2-type structure and an antiferromagnetic ground state,which is similar to the iron-based superconductor BaFe2As2.High quality and large size single crystal sample of BaMn2Bi2 were prepared by flux method.The crystal structure,chemical composition,electrical transport properties of single crystal sample were characteristiced by the experimental equipments such as X ray diffraction,energy spectrum analysis system,and physical property measurement system,and the anisotropy of the electrical transport properties were systematic studied.It is found that the in-plane resistivity and out-of-plane resistivity decrease with decreasing temperature and exhibit a bad metallic behavior between 300 K and 100 K.However,the in-plane resistivity and out-of-plane resistivity increase with decreasing temperature and exhibit a semiconductor behavior with the excitation energy about 2.5-3 meV below 100 K.Applying a magnetic field of 9 T,the magnetoresistance for the two directions are only about 5%above 100 K,and the magnetoresistance decrease with decreasing temperature below 100 K and reached as high as about-18%at 1.8 K.Whether a magnetic field is applied or not,there is no obvious anisotropy for both of the in-plane resistivity and out-of-plane resistivity.

关 键 词：铁基超导 ThCr2Si2结构 各向异性 金属-绝缘体转变 

分 类 号：O441.6[理学—电磁学]