GdBaCuO超导薄膜T_c值的优化实验研究

OPTIMIZATION OF T c IN EPITAXIAL GdBaCuO SUPERCONDUCTING THIN FILM BY INVERTED CYLINDRICAL SPUTTERING

ＧｄＢａＣｕＯ超导薄膜Ｔｃ值的优化实验研究李言荣刘兴钊徐进（电子科技大学信息材料工程学院，成都６１００５４）Ｊ．ＧＥＥＲＫＲ．ＳＭＩＴＨＹ（ＩＮＦＰ，ＦｏｒｓｃｈｕｎｇｓｚｅｎｔｒｕｍＫａｒｌｓｒｕｈｅ，Ｄ７６０２１，Ｇｅｒｍａｎｙ）（１９９７年１...

Thin films of GdBaCuO(GBCO) compound have been deposited in situ onto LaAlO 3 single crystal substrates by inverted cylindrical sputtering.The variation of superconductive properties of the thin films with the substrate temperature and sputtering pressure has been systematic investigated.By the optimization of deposition parameter,high quality c axis epitaxial GBCO thin films of T co >92K were reproducibly grown at the substrate temperature of 720—820℃ with a low deposition total pressure (40Pa).The T co of the best sample is as high as 93 2K.Only by changing the target composition into GdBa 2Cu 4O y (Gd 124 ),was it observed that the samples always contain some a axis oriented films,impling that excess copper would favour a axis growth in thin films,and the T c of the samples is lower than that with Gd 123 target.The superconductivity of the thin films under high substrate temperature was clearly improved by the procedure of special post oxygenization at 400℃ in ozone atmosphere.These results are very useful to further prepare large area thin films of GBCO.