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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.
A high quality Tl2Ba2CaCu2O8 (Tl-2212) superconducting thin film was fabricated on a 2-inch double-sided sapphire substrate by using CeO2 as a buffer layer. The cerium was used as a sputtering target and the c-axis texture was grown by RF magnetron reactive sputtering The effects of different growth conditions on the crystal structure and surface morphology of the CeO2 buffer layer were investigated.The DC magnetron sputtering and post-heat treatment were used to prepare the superconducting thin films.The scanning electron microscopy (SEM) The superconducting thin films have a dense crystal structure and a uniform and flat surface topography.The results of X-ray diffraction (XRD) show that the superconducting thin films are pure Tl-2212 phase with the c-axis perpendicular to the substrate surface texture and epitaxial growth On the CeO2 buffer layer, the results of electromagnetic measurements show that the superconductivity of the films has a high degree of in-plane uniformity and two-sided uniformity with a critical transition temperature Tc of about 105K and a critical current density Jc (77K, 0T) of 1.2 ± 0.1 MA / cm2 and (1.25 ± 0.1) MA / cm2, the microwave surface resistance Rs (77K, 10GHz) is 390μΩ.