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.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
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)
