SUPERCONDUCTING YBA2CU3O7 FILMS PREPARED BY AEROSOL METAL-ORGANIC CHEMICAL-VAPOR-DEPOSITION ON AL2O3 SUBSTRATE WITH CEO2 BUFFER LAYER

Superconducting YBa2Cu3O7 films with a CeO2 buffer layer were prepared by aerosol MOCVD on Al2O3 substrates. X-ray diffraction and high-reso lution electron microscopy revealed a high degree of epitaxy of the YB a2Cu3O7/CeO2 heterostructure without any traces of interfacial reactio n. Although both YBa2Cu3O7 and CeO2 films grow in a relaxed state, add itional strain is incorporated into the structure during cooling from the deposition temperature, which results in a decrease of the lattice parameters perpendicular to the substrate surface. The YBa2Cu3O7 film s exhibit a critical temperature T-c(R=0) = 84-88 K With a critical cu rrent density of 3 x 10(9) A m(-2) at T = 77.3 K. The angular dependen ce of the critical current at temperatures above 40 K in magnetic fiel ds up to 0.5 T indicates that the YBa2Cu3O7 films grown by aerosol MOC VD on the CeO2/Al2O3 substrate behave as three-dimensional anisotropic superconductors.