Crystallinity and surface morphology of YBCO thin films using an amorphous buffer layer deposited at a low temperature

We have investigated the crystallinity and surface morphology of main YBCO films and buffer layers deposited on an MgO substrate by a low temperature buffer layer deposition technique. A significant improvement in the crystalline quality of the YBCO film is achieved when an amorphous buffer layer of 100 [nm] in thickness on bare MgO substrate annealed at 930[( degree)C] is crystallized by annealing temperature 950[(degree)C] for 1 hour in an air atmosphere. The surface of main YBCO films has pyramid like large grains when YBCO films have good crystallinity. We confirmed that YBCO films grown on a well-crystallized buffer layer had better crystallinity than ones grown on bare MgO substrate.