蓝宝石基片上制备大面积Tl_2Ba_2CaCu_2O_8超导薄膜  

Fabrication and properties of large area Tl_2Ba_2CaCu_2O_8 superconducting thin film on sapphire substrate

作　　者：游峰[1] 季鲁[1] 谢清连[1] 王争[1] 岳宏卫[1] 赵新杰[1] 方兰[1] 阎少林[1] 

机构地区：[1]南开大学电子信息科学与技术系,天津300071

出　　处：《物理学报》2010年第7期5035-5043,共9页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:2006CB601006);国家高技术研究发展计划(批准号:2009AA03Z208)资助的课题~~

摘　　要：在2英寸双面蓝宝石基片上采用CeO2作为缓冲层制备了高质量Tl2Ba2CaCu2O8(Tl-2212)超导薄膜.以金属铈作为溅射靶材,采用射频磁控反应溅射法生长了c轴织构的CeO2缓冲薄膜,并研究了不同生长条件对于CeO2缓冲层的晶体结构及表面形貌的影响.超导薄膜采用直流磁控溅射和后热处理的方法制备.扫描电子显微镜(SEM)图像显示,超导薄膜具有致密的晶体结构和均匀平坦的表面形貌.X射线衍射(XRD)结果表明,超导薄膜为纯的Tl-2212相,具有c轴垂直于基片表面的织构并外延生长在CeO2缓冲层上.电磁测试结果显示了薄膜的超导电性具有高度的面内均匀性和两面一致性,临界转变温度Tc为105K左右,临界电流密度Jc(77K,0T)分别为1.2±0.1MA/cm2和(1.25±0.1)MA/cm2,微波表面电阻Rs(77K,10GHz)为390μΩ.High quality large area Tl2Ba2CaCu2O8（Tl-2212） superconducting thin films were fabricated on CeO2 buffered two-side sapphire substrates.Using metallic cerium target as the sputtering source,CeO2 buffer film with c-axis orientation was deposited by radio frequency reactive magnetron sputtering,and the influence of preparation conditions on the structure and surface morphology of the CeO2 layer was studied.The Tl-2212 superconducting thin film was fabricated on CeO2 buffered sapphire substrate by direct current magnetron sputtering and post annealing.Scanning electron microscope showed that the film has a compact microstructure with uniform flat surface.The X-ray diffraction indicated that the film was pure Tl-2212 phase with c-axis perpendicular to the substrate surface,and epitaxially grown on the CeO2 buffered sapphire.The superconducting film exhibited excellent uniform electric properties.The critical transition temperature Tc was around 105 K,the critical current density Jc（77 K,0 T） was around（1.2±0.1） MA /cm2 and（1.25±0.1） MA/cm2,respectively,and the microwave surface resistance Rs（77 K,10 GHz） of the film was as low as 390 μΩ.

关 键 词：Tl-2212超导薄膜 CeO2缓冲层 蓝宝石基片 

分 类 号：O484.1[理学—固体物理]