Spray Pyrolysis of<tex>$rm YBa_2rm Cu_3rm O_7-rm x$</tex>Coated Conductors on

Abstract

YBa/sub 2/Cu/sub 3/O/sub 7-x/ films have been deposited using spray pyrolysis on (100) SrTiO/sub 3/ substrate. An extended study on the optimization of the composition, carrying gas flow, deposition temperature as well as annealing time was performed. It was found that these parameters are strongly correlated and affect the morphology, orientation and superconducting properties of the YBCO films. As grown films already exhibit J/sub c/ values of 10/sup 4/ A/cm/sup 2/, thus indicating that the correct structure is already formed during deposition. It was found that the temperature gradient in the pyrolysis zone played a fundamental role during the deposition. After modification of this heat gradient by adding a metallic susceptor, a noticeable improvement in the properties of the films was obtained. An in-plane orientation FWHM value of 0.70/spl deg/ was measured from the (102) pole figure. The films exhibited a T/sub c/ onset of 91 K (/spl Delta/T/sub c/=1.5 K), while the J/sub c/ value at 77 K in self-field approached 10/sup 5/ A/cm/sup 2/. Based on an assumed typical intragranular critical current density, we found a 40/spl times/40 /spl mu/m area in our best film where the assumed critical current density is well above 10/sup 6/ A/cm/sup 2/.