MICROSTRUCTURE OF THE INPLANE ALIGNED ALPHA-AXIS ORIENTED YBA(2)CU(3)O(7-X)THIN FILMS ON LASRGAO4(100) SUBSTRATES

We report the microstructure of the in-plane aligned a-axis oriented Y Ba2Cu3O7-x thin films grown on LaSrGaO4 (LSGO) (100) substrates by a P rBa2Cu3O7-x (PBCO) template pulsed laser deposition method. We observe d a 90 degrees [101] basal-plane-faced tilt grain boundary by high-res olution transmission electron microscopy (HRTEM). By observing the cro ss-sectional HRTEM images of the interface between the PBCO template l ayer and the substrate, we determined that the wavy surface of the sub strate consists of the (101) planes. The images and the selected area diffraction patterns showed that a mixed c- and b-axis oriented PBCO l ayer was initially grown on the substrate, followed by pure b-axis ori ented PBCO growth. We explained that the c-axis oriented growth was th e result of the growth of PBCO (019) planes on LSGO (101) planes.