Non-resonant microwave absorption and critical current density in YBa 2Cu 3O x films prepared by laser ablation

Abstract

High-quality YBa 2Cu 3O x superconducting thin films have been prepared on (100)MgO substrates by the laser ablation technique, and characterized by non-resonant microwave absorption (NRMA) with a field modulation, magnetization and four-probe measurements. The pinning properties derived from the NRMA spectra for various YBa 2Cu 3O x films are correlated with the critical current densities T c. A relatively high- J c film prepared from YBa 2Cu 3O x composition target using a Nd:YAG laser shows a derivative spectrum and a large hysteresis in the NRMA spectra. The highest- J c film prepared from an YBa 2Cu 4O x composition (YBa 2Cu 3O x+CuO) target using an ArF excimer laser does not show a derivative NRMA spectrum, suggesting a strong pinning property.