Microstructure of YBCO thin film deposited on LaAlO3 substrate

Microstructure of high Jc YBCO thin film deposited on the 30mm×30mm LaAlO3 substrate by using a hollow cylinder cathode DC magnetron sputtering technique was studied with an AEM and HREM. The c-axis oriented YBCO thin film included a few Y2 BaCuO5 particles and spindle-like Y2O3 oxide. [001] edge and screw dislocations, stacking faults and other planar defects, lattice distorted regions less than 15 nm and cation vacancies were found in the film. On the substrate surface the first layer film atoms were CuO and CuO2 layer so that the BaCuO2 and YBaCu2O5 phases were formed at the interface. The step-like substrate surface, small pits on the surface and dislocations in the substrate surface layer obviously effected on the epitaxial growth of the film and formation of the defects in the film. the effect of the defects on the Jc was discussed.