High critical current densities in YBa2Cu3O7−x thin films formed by metalorganic chemical vapor deposition at 730 °C

YBa2Cu3O7−x superconducting thin films with a critical current density of 2.3×106 A/cm2 at 77.7 K and 0 T were prepared by a metalorganic chemical vapor deposition process. The films were formed in situ on LaAlO3 at a substrate temperature of 730 °C in 2 Torr partial pressure of N2O. Resistivity and magnetic susceptibility measurements of the as-deposited films show a sharp superconducting transition temperature of 89 K with a narrow width of less than 1 K. Critical current densities were measured by the dc transport method with a patterned bridge of 120 μm×40 μm. Both x-ray diffraction and high-resolution electron microscopy measurements indicate that films grew epitaxially with the c axis perpendicular to the surface of the substrate.