蓝宝石基片上制备大面积Tl2Ba2CaCu2O8超导薄膜

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

Fabrication and properties of large area Tl2Ba2CaCuO8 superconducting thin film on sapphire substrate

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 T_c was around 105 K, the critical current density J_c(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 R_s (77 K, 10 GHz ) of the film was as low as 390 μΩ.