Preparation and magnetic properties of Ba/sub 1-x/K/sub x/BiO/sub 3+y/ and YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// single crystal films

Large area Ba/sub 1-x/K/sub x/BiO/sub 3+y/ and YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// films were grown by LPE techniques on (Ba,K)BiO/sub 3/ and NdGaO/sub 3/ substrates, respectively. The good quality of epitaxy and small crystal mosaicity of the films were confirmed by X-ray measurements. Chemical homogeneity and microstructure of the films and interfaces were investigated by SNMS, HREM and SEM, depending on growth parameters. A comparative study of magnetic hysteresis loops in the reversible (irreversible) regions were done for both types of films. The VSM data show that the irreversible line follows the flux creep model.