STRUCTURAL CHARACTERIZATION OF YBA2CU3O7-DELTA Y2O3 COMPOSITE FILMS/

Using 4-circle x-ray diffraction and transmission electron microscopy, we have studied the microstructure and in-plane orientation of the ph ases present in thin film composite mixtures of YBa2Cu3O7-delta and Y2 O3. We see a high degree of in-plane orientation and have verified a p revious prediction for the in-plane order of Y2BaCuO5 on (110) MgO. Tr ansmission electron microscopy shows the composite films to be a mixtu re of two phases, with YBCO grain sizes of approximate to 1 mu m. We h ave also compared our observations of the in-plane order to the predic tions of a modified near coincidence site lattice model.