摘要
本文研究了Na掺杂对MTG -YBCO(YBa2 -xNaxCu3 Oy+ 4 0mol%Y2 BaCuO5 ,x =0 .0、0 .1、0 .2 )生长织构及其超导性能的影响。适量Na的掺入有利于MTG -YBCO沿 (ab)面的生长 ,改善晶体生长的宏观形貌。同时 ,掺Na后MTG -YBCO试样的Tc ,on变化不大 ,但Tc ,off随掺杂量x的增加而降低 ,即超导转变宽度ΔT增大。适量Na掺杂改善了MTG -YBCO的临界电流密度特性 ,并在临界电流随外磁场变化的曲线中观察到第二峰现象。经 90 0℃高温退火处理后 ,第二峰消失 ,其后的 40 0℃吸氧处理使Jc随吸氧时间增长而增加 ,且第二峰现象重现。本文同时探讨了Na掺杂MTG
The effects of Na addition in the MTG-YBCO (YBa 2-x Na xCu 3O y+40mol% Y 2BaCuO 5) system with x=0.0, 0.1, 0.2 on the texture and superconducting properties have been investigated. It was observed that there is little change on T c,on as x 0.2 for these materials, but T c,off decreases with x increase. That is, the larger the Na content in the composition, the broader is the superconducting transition region. With certain Na addition, MTG-YBCO showed an improved critical current density characteristic and a second peak with increasing magnetic field. The post-annealing at 900℃ reduced the critical current density and eliminated the second peak. The followed oxygenation at 400℃ increased the critical current density and recovered the second peak again. These might be connected with the formation of low T c phase owing to the addition of Na. At the same time, Na doping improved the texture of MTG-YBCO and result in a increase of the crystal growth rate in (ab) plane.
出处
《功能材料与器件学报》
CAS
CSCD
2000年第1期50-54,共5页
Journal of Functional Materials and Devices
