INPLANE ORIENTATION CONTROL OF (001)YBA2CU3O7-DELTA GROWN ON (001)MGOBY PULSED ORGANOMETALLIC BEAM EPITAXY

Thin films of (001) YBCO are grown on epitaxially polished (001) MgO b y pulsed organometallic beam epitaxy. The in-plane orientation of the film is controlled by the thickness of a BaO layer, grown in situ, pri or to the YBCO growth-Eor thin BaO layers(< approximate to 7 x 10(14) Ba/cm(2)) the films grown [11O]YBCO\\[100]MgO. For thick BaO layers (> approximate to 11 x 10(14) Ba/cm(2)) the films grow [100]YBCO\\[100]M gO. A mechanism that relates the change in YBCO in-plane orientation t o a change in the structure of the initial BaO layers with BaO thickne ss is described. (C) 1996 American Institute of Physics.