Highly oriented superconducting thin films derived from the sol-gel process

Highly oriented YBa2Cu3O6+x superconducting thin films have been developed via sol-gel processing. Film deposition involved spin coating a ‘‘partially hydrolyzed’’ metal-alkoxide stock solution onto single-crystal [100] SrTiO3 substrates. Although scanning electron microscopy revealed the film consisted of oriented polycrystallites, from the broad statistical x-ray diffraction data the 1000 Å film ‘‘appeared’’ to be single crystal with moderate mosaic spread (i.e., full width at half-maximum was 0.3° in θ at a 2θ of 55°). No twinning of the crystal was found in any of the three orthogonal directions (2θ, φ, χ). The onset temperature Tc for the film was 55 K while the critical current density Jc was found to be 102 A/cm2.