用阳离子置换法制备汞系高温超导薄膜

FABRICATION OF Hg-BASED HIGH-T_c SUPERCONDUTING THIN FILMS USING CATION EXCHANGE PROCESS

介绍了最近发明的一种制备汞系高温超导薄膜的新方法—阳离子置换法．采用Ｔ１ 系外延超导薄膜作为先驱薄膜，将Ｔ１ 系超导薄膜在Ｈｇ 气氛下进行热处理，用Ｈｇ 置换先驱薄膜中的Ｔ１，进而生成Ｈｇ 系外延超导薄膜．用此方法，成功地在ＬａＡｌＯ３ （００１）衬底上制做出了高质量的ＨｇＢａ２ＣａＣｕ２Ｏｘ 超导薄膜．Ｘ－光衍射θ－２θ扫描和极图测试表明，薄膜具有很纯的超导相和很好的外延结构．超导临界温度可达１２２Ｋ．在７７Ｋ温度下，临界电流密度达到３．４×１０６ Ａ／ｃｍ ２，在１１０Ｋ 温度下，临界电流密度仍可保持在０．７×１０６Ａ／ｃｍ ２ ．

Cation exchange method for the fabrication of Hg\|based superconducting thin films has been developed. T1\|based superconducting thin films are chosen as the precursor films and annealed in Hg vapor atmosphere. During the annealing process, T1 is exchanged for Hg and the T1\|based superconducting thin films are transformed to Hg\|based superconducting thin films. Using this method, high quality HgBa 2CaCu 2O x thin films on LaAlO 3 (001) substrates have been fabricated successfully. XRD θ\|2θ scans and pole figures prove that the HgBa 2CaCu 2O x thin films have pure superconducting phase and complete epitaxial structure on the substrates. The critical transition temperature of the Hg\|based thin film is as high as 122K. The critical currents of 3.4×10 6 A/cm 2 at 77K and 0.7×10 6 A/cm 2 at 110K have been obtained.