空气中熔化生长Nd-Ba-Cu-O超导体的Ar气处理与相稳定性  

Argon post_treatment and phase Stability on Nd-Ba-Cu-O Superconductor Fabricated by Melt Processing in Air

作　　者：钞曦旭[1] 杨万民[1] 边小兵[1] 王振邦[1] 

机构地区：[1]陕西师范大学物理学与信息技术学院,陕西西安710062

出　　处：《陕西师范大学学报（自然科学版）》2002年第4期50-53,共4页Journal of Shaanxi Normal University：Natural Science Edition

摘　　要：利用X射线衍射及扫描电镜等方法,研究了Ar气处理温度对空气中熔化生长的NdBa2Cu3O7-δ+20%Nd4Ba2Cu2O10样品超导性能和组织结构的影响.结果表明,在大气环境中放置20个月的情况下,经900℃Ar气处理的样品易碎裂,且超导性能明显降低,显示出超导相的不稳定性;在500℃下经较长时间Ar气处理的样品,起始转变温度可达93K,且结构和性能均较稳定.A series of superconductors with the compositions of NdBa2Cu3O7-δ+wNd4Ba2Cu2O10 (w=20 wt.%) are fabricated by a melt_processing technique in air and post_treatment in argon. The effect of post_treatment on superconductivity and on phase stability are studied by means of XRD, SEM and AC susceptibility measurement. The results show that the post_treatment in Ar displays a dramatic improvement of superconductive properties even at lower treatment temperature. The treatment temperature above 900℃, however, induces the lower stability although it is in favor of superconducting properties for fresh samples. It is proposed that post_treatment in Ar at lower temperature (500℃) for long time is likely to produce the Nd_Ba_Cu_O bulk superconductor with higher quality and stability.

关 键 词：熔化生长 Nd-Ba-Cu-O超导体 超导电性 Ar气处理 相稳定性 组织结构 

分 类 号：O511[理学—低温物理]