High Jc thin films of YBa 2Cu 3O 7

Abstract

Polycrystalline YBa 2Cu 3O 7 thin films have been prepared on (001) SrTiO 3 substrates by sputtering and annealing. X-Ray diffraction experiments show the presence of epitaxial a and c orientated crystallites, but no b orientated ones are found. Critical current densities of up to 5 × 10 5 A cm 2 at 77 K have been observed in narrow laser-delineated tracks. It is found that the value of critical current density is insensitive to the length of the track and to the voltage criterion used. The effect of magnetic fields up to 8 T on the critical current has been measured.