层状过渡金属化合物CaMn_2Bi_2的物理性质研究  

Physical properties of layered transitional metal compound CaMn_2Bi_2

作　　者：杨艺 傅瑜[1] 宋海珍[1] 马奔原[1] 张萍[1] 冷玉敏[1] 何俊宝 YANG Yi;FU Yu;SONG Haizhen;MA Benyuan;ZHANG Ping;LENG Yumin;HE Junbao(School 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,河南南阳473061

出　　处：《南阳师范学院学报》2019年第1期1-5,共5页Journal of Nanyang Normal University

基　　金：国家自然科学基金(11404175;21607083);河南省自然科学基金(182300410274);南阳师范学院青年项目(2018QN007);南阳师范学院实验(实训)室开放项目(SYKF2017056)

摘　　要：利用Bi作为助熔剂制备出了层状过渡金属化合物CaMn_2Bi_2单晶样品,通过X射线衍射、能谱分析系统、综合物性测量系统等测试设备对该单晶样品的晶体结构、化学成分、电学和磁学性质进行了测量和表征.结果表明:CaMn_2Bi_2是一个层状过渡金属化合物,具有三角晶系Ca Al_2Si_2型的晶体结构,Mn2+排列成三角格子层.磁化率在150 K表现出反铁磁行为,但是在反铁磁转变温度以上磁化率不满足Curie-Weiss行为表现出鼓包行为,说明在反铁磁转变温度以上系统中存在着很强的反铁磁关联.电阻率从300 K开始随温度降低而降低,表现出金属线性行为;在150 K附近随温度降低而急剧地降低,这与发生反铁磁转变是相关的;直到70 K附近电阻率降到最低,随后在低温下随温度降低而升高,表现出半导体行为.Single crystal sample of layered transitional metal compound CaMn2Bi2 was prepared by bismuth flux method.The crystal structure,chemical composition,electrical and magnetic properties of single crystal sample were systematic measured and characteristiced by many kinds of experimental equipments such as X ray diffraction,energy spectrum analysis system and physical property measurement system.The experiment results indicate that the compound CaMn2Bi2 is a layered transitional metal compound and crystalizes in the trigonal CaAl2Si2 type structure,which is characterized by triangular Mn^2+layers.The magnetic susceptibility shows an antiferromagnetic transition at 150 K.Above the temperature of antiferromagnetic transition,the magnetic susceptibility doesn’t satisfy the requirement of Curie-Weiss behavior and shows a broad maximum behavior,which suggests strong antiferromagnetic correlations exist in the paramagnetic state.The resistivity decreases linearly with decreasing temperature and exhibits metallic behavior from 300 K.And it shows an abrupt decrease at about 150 K,which is consistent with the antiferromagnetic transition.The resistivity reaches a low point at about 70 K.Then it increases with decreasing temperature and exhibits semiconductor behavior at low temperature.

关 键 词：层状过渡金属化合物 单晶制备 物理性质 

分 类 号：O441.6[理学—电磁学]