High Current Densities in Superconducting Films from Magnetization

Epitaxial thin films of YBa2Cu3O7-xmade by laser ablation have the CuO planes parallel to the film surface. In the CuO planes critical currents of Jc≈40× 106 amps/cm2are found at 5K in zero field. Multi-layered films with Gd replacing Y each. 0lμm in thickness have Jcnearly 140× 106 amps/cm2. This higher value is perhaps due to additional point defects. Perpendicular to the CuO planes magnetization studies indicate strong pinning effects attributed to the CuO planes acting as barriers to flux motion. © 1990 IEEE