Effect of laser irradiation on superconducting properties of laser-deposited YBa2Cu3O7 thin films

The superconducting properties of YBa2Cu3O7 thin films subjected to controlled pulsed nanosecond laser irradiation were investigated. Irradiated films on (100) LaAlO3 substrates showed excellent thermal stability with the temperatures for zero resistance of approximately 90 K even after irradiation with energy densities greater than 250 mH/sq cm. The critical current density Jc of the films showed an enhancement at low energy densities, followed by a drastic decrease in Jc above a certain energy threshold. This decrease has been correlated with the melting threshold. Similar results are observed for YBa2Cu3O7 films on (100) yttria-stabilized zirconia substrates; however, the energy density was found to be much smaller.