A BILAYER BUFFER USING 214T Eu2CuO4 AND CUBIC YSZ FOR GROWING YBa2Cu3Oy THIN FILMS ON Si

Highly epitaxial thin films of YBa2Cu3Oy (YBCO) have been successfully grown on Si using a double buffer of Eu2CuO4 (ECO)/(yttrium-stabilized zirconia) YSZ. The severe reaction between Si and YBCO is blocked by YSZ, and the crystallinity and superconductivity of the grown YBCO due to the lattice mismatch between YBCO and YSZ are improved by the ECO layer. The grown films were characterized by high-resolution X-ray diffraction, grazing incidence X-ray reflection, scanning electron microscopy (SEM), and Doppler broadened annihilation radiation spectroscopy, respectively. Very clear interfaces were found at YBCO/ECO/YSZ boundaries without any intermediate layer. The YBCO film surface was more smooth and stable. The results obtained indicate that highly epitaxial YBCO thin films can be successfully grown on Si wafers, demonstrating advantages of such a double buffer structure.