纳米级晶体缺陷诱发YBCO超导薄膜的强磁通钉扎性能

It is commonly expected that there are strong vortex pinning force when YBa2Cu3O7-δ (YBCO) coated conductors are served at high temperature and different magnetic field orientations angled to YBCO c-axis. In this paper, we show a simple approach, epitaxially growing YBCO film on Ba0.7Sr0.3TiO3 (BST) microarrays buffered LaAlO3 (LAO) substrate, to introduce nanoscale crystalline defects within YBCO matrix. High concentration nanodefects, including nanotwins, intergrowth, stacking faults and plane buckling were observed by high-resolution transmission electron microscopy. It is demonstrated through magnetization vs. magnetic field strength measurement that these nanodefects can endow quasi-isotropic vortex pinning characteristic to nanostructured YBCO films to enable power applications of coated conductors. It is believed that nonsuperconductivity regions (the dimension near to the order of ξ, the coherence length of YBCO) caused by the nanodefects are the effective pinning centers to inhibit flux creep. Therefore, large pinning energy can be easily obtained for YBCO films if considerable nanodefects can be introduced into epitaxial YBCO matrix no mater what methods are employed to produce YBCO nanocomposite film.