La和Pr掺杂对Ba_(0.6)K_(0.4)BiO_3结构及超导电性的影响(英文)  

Effects of La- and Pr-Substitution on the Structure and Superconductivity of Ba_(0.6)K_(0.4)BiO_3

作　　者：崔雅静[1] 陈永亮[1] 程翠华[2] Charles C.Sorrell 赵勇[1,2] 

机构地区：[1]西南交通大学磁浮技术与磁浮列车教育部重点实验室,四川成都610031 [2]新南威尔士大学

出　　处：《稀有金属材料与工程》2015年第9期2081-2085,共5页Rare Metal Materials and Engineering

基　　金：National Natural Science Foundation of China(50872116,11004162,11104224);Research Fund for the Doctoral Program of Higher Education of China(20110184120029);Fundamental Research Funds for the Central Universities(SWJTU11BR063,2682013CX004,2682013ZT16,SWJTU11ZT31);National Magnetic Confinement Fusion Science Program(2011GB112001);Program of International S&T Cooperation(2013DFA51050)

摘　　要：利用熔盐法制备了Ba0.6-y La y K0.4Bi O3和Ba0.6-z Pr z K0.4Bi O32个系列的样品,其中La和Pr的掺杂量y和z分别为0,0.025,0.05,0.1,0.2,0.3,0.4。X射线粉末衍射结果显示,Pr掺杂使得BKBO晶体结构由最初的立方晶系转变成为正交晶系,但是La掺杂样品却没有发生此种晶体结构的变化。La掺杂样品Ba0.6-y La y K0.4Bi O3的准晶格参数a p随掺杂量的增大而线性减小,其变化遵循a p=4.28257–0.02469y(0.025≤y≤0.4)的规律。样品磁性测量结果表明,掺杂样品的超导转变温度T c均随着掺杂量的增大而系统性地减小,并且当掺杂量达到0.2时,2个系统中的超导转变均消失。认为掺杂引起的晶体结构扭曲及铋化合价的不均衡导致了BKBO掺杂系统超导电性的变化。Two compositional series based on Ba0.6-y La y K0.4Bi O3 and Ba0.6-z Pr z K0.4Bi O3, with y and z being 0, 0.025, 0.05, 0.1, 0.2, 0.3, 0.4, were synthesized using a molten salt method. X-ray powder diffraction data reveal that the initially undoped cubic crystal symmetry expands slightly to orthorhombic with Pr substitution but not with La substitution. A linearly reduction of the pseudo-lattice parameter following a p=4.28257–0.02469y（0.025≤y≤0.4） can be observed in Ba0.6-y La y K0.4Bi O3. A systematic decrease of the transition temperature, T c, is clarified by magnetic measurements and the superconductivity is finally vanished at y, z = 0.2 owing to the distortion of the crystal structure and the disproportionations of bismuth valence.

关 键 词：Ba0.6K0.4BiO3 掺杂 晶体结构 熔盐法 

分 类 号：O611[理学—无机化学]