Preparation of superconductive Y-Ba-Cu-O/Bi-Sr-Ca-Cu-O heteroepitaxial bilayer films by Nd:YAG laser ablation

Here we report for the first time the heteroepitaxial growth of as-deposited superconductive YBa₂Cu₃O_7-x (YBCO)/Bi₂Sr₂CaCu₂O_8-y (Bi-2212) and Bi-2212/YBCO bilayer films on MgO (100) substrates by using the 4th harmonics of a Nd:YAG pulsed laser beam. The Bi-2212 thin films had single-phase crystallinity and a zero resistance temperature (T_c0) of 71.4 K. Under similar preparation conditions, YBCO thin films showed single phase and T_c0=88.5 K. The YBCO/Bi-2212 bilayer films grown with an in situ process´ showed c-axis orientation and single phase for both YBCO and Bi-2212, Moreover, X-ray pole figures indicated that YBCO/Bi-2212 and Bi-2212/YBCO bilayer films grow heteroepitaxially with in-plane orientation of the Bi-2212 [100] direction parallel to the [110] direction of YBCO