高T_c(Hg,Pb)-1223相超导体的EPMA研究  

EPMA STUDY OF (Hg, Pb)-1223 PHASE SUPERCONDUCTOR WITH HIGH T_c

作　　者：张文兰[1] 王汝成[1] 赖鸣远[1] 陈小明[1] 邵惠民[2] 

机构地区：[1]南京大学成矿机制国家重点实验室,南京210093 [2]南京大学物理系,南京210093

出　　处：《低温物理学报》1997年第1期33-38,共6页Low Temperature Physical Letters

基　　金：国家超导研究开发中心;南京大学成矿机制国家重点实验室资助项目

摘　　要：在HgBaZeaZeu30:+。(Hg一1223相)超导体中,我们以pb部分代替Hg,成功地合成了(Hg,Pb)一1223相超导体,并对这些样品进行了XRD、TEM、SEM和EDX等分析.本文着重报导EMPA(电子探针分析)分析的结果:在我们最佳合成的(Hg,Pb卜1223超导样品口飞R一。=135K,了,.d'二143K)中,正离子比为Hg:Pb:Ba:Ca:Cu=0.66,0.34,2, 1.98:2.97,氧含量为8.42;以及样品的主相为(Hg,Pb卜1223相,少量杂相为HgCaO:、CuO等等.以上结果与XRD、TEM和EDx等分析结果一致.特别是超导相中的氧含量与中子衍射分析结果一致.最后得出最佳超导样品的分子式为(Hg_(0.66)Pb_(0.34))Ba_2Ca_(1.98)Cu_(2.97)O_(8.41)Partial substitution of Pb on the Hg site was successfully performed in the Hg-based 1223 phase HgBa_2Ca_2Cu_3O_(8+δ) superconductor, resulting in an increasernent of the superconductor transition temperature to T_c^(R=0)=135K and T_c^(dia)=143K for the optimun sample. These samples were examined by X-Ray Diffraction (XRD), Transmisson Electron Microscopy (TEM), SEM, EDX, and Neutron Diffraction study. The main purpose of this work was to report the results obtained by Electron Probe Mieroanalyzer (EPMA) for the optimally substituted HgBa_2Ca_2Cu_3O_(8+δ) sample with Pb, which were as follws: The catio ratio of Hg: Pb: Ba: Ca: Cu=0.66: 0.34:2:1.98:2.97, and the oxygen content δ=0.41, leading to chemical formula of (Hg_(0.66)Pb_(0.34))Ba_2Ca_(1.98)Cu_(2.97)O_(8.41). In addition, the Hg-1223 as the dominant phase and no signifieation impuri- ty phases such as CaHgO_2 and CuO can be identified also by EPMA investigation. These results are consistent with those obtained by XRD, TEM and EDX. Particularly the oxygen content calculated on the basis of EPMA analyses is exactly the same as that determined by the neutron diffraction data with high precision. Further investigations on the related phase diagrams are needed to design a better synthesis procedure, and more detailed work is currently underway.

关 键 词：高TC HBCCO EPMA 超导体 

分 类 号：TM262[一般工业技术—材料科学与工程]