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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 -YBCO的这种临界电流密度行为形成的机制
In this paper, the effects of Na doping on the growth texture and superconductivity of MTG-YBCO (YBa2-xNaxCu3Oy + 4 0mol% Y2BaCuO5, x = 0.01,0.1,0.2) were investigated. Addition of appropriate amount of Na favors the growth of MTG-YBCO along the (ab) surface and improves the macroscopic morphology of the crystal growth. At the same time, Tc, on of MTG-YBCO sample after adding Na did not change much, but Tc, off decreased with the increase of doping content, that is, the superconducting transition width ΔT increased. An appropriate amount of Na doping improves the critical current density characteristics of MTG-YBCO, and the second peak phenomenon is observed in the curve of the critical current with the change of the external magnetic field. The second peak disappeared after annealing at 90 0 ℃, and the subsequent 40 ℃ oxygen absorption increased Jc with the increase of oxygen absorption time, and the second peak phenomenon reappeared. This paper also discusses the Na doped MTG-YBCO this critical current density behavior formation mechanism