Electrical transport dissipation effects in epitaxial Y1Ba2Cu3O7-x thin films

The electrical transport properties of a series of Y1Ba2Cu3O7-x thin films deposited onto single crystal substrates by thermal coevaporation and laser ablation were investigated. For fully epitaxial, c-oriented films on (001) substrate surfaces, the critical current density Jc showed large high-field enhancements for the film aligned with H parallel to the copper-oxygen planes. With H parallel c, a precipitous decay of Jc with increasing field is described by thermally activated flux motion. Films on (110) SrTiO3 substrates were comprised of finely-divided arrays of grains having [110], and left-angle 103 right-angle-type orientations, and exhibited granular behavior. For these triaxial films, the transport dissipation was also thermally activated but with much smaller energy barriers