Pb添加对MOD-YBCO超导膜结构和临界电流密度的影响

Influence of Pb Addition on the Structure and Critical Current Density of MOD-YBCO Superconducting Thin Films

使用Pb添加方法改善钇钡铜氧(YBCO)超导膜的金属有机物沉积(MOD)制备中的形核和生长过程。通过引入一定量的三水合乙酸铅,配制出均一稳定的含Pb前驱溶液,经过涂覆和热处理制备YBCO超导膜,然后测量YBCO超导膜的微观结构和临界电流密度(Jc),从而研究了不同Pb添加量和不同水分压的影响。研究结果表明,当热处理期间的水分压较低(露点为25℃)时,Pb添加会使YBCO膜形成气孔,出现局域不致密的现象,从而导致Jc明显下降。当热处理期间的水分压较高(露点为45℃)时,使用Pb添加方法制备的YBCO膜致密程度提高,而且非c轴取向YBCO晶粒得到抑制,当Pb添加量为1.1wt%时YBCO超导膜的Jc最优,可达到3.7 MA/cm2(自场,77 K,370 nm厚)。

Pb addition was used to improve the nucleation and growth of YBa2Cu307.8 （YBCO） superconducting films fabricated via the metal organic deposition （MOD） process. By adding lead （Ⅱ） acetate trihydrate, uniform and stable Pb-containing precursor solution could be obtained. And the final YBCO superconducting films were fabricated through the coating and heat treatment steps. The micro- structure and critical current density （Jc） were characterized, and the influences of Pb addition amount and water pressure were investigated. When the water pressure is low （at dew point of 25 ℃ , Pb addition leads to the occurring of pores and nondense areas, hence degrading Jc of YBCO films. When the water pressure is raised （ at dew point of 45 ℃ ） , the YBCO films fabricated using Pb addition are densified, and the a/b-axis orientated YBCO grians could be suppressed. Jc of YBCO films is optimal when the amount of Pb addition is 1. lwt% , which is 3.7 MA/cm^2（self-field, 77 K, 370 nm thick）.