Switching of a superconducting Y-Ba-Cu-O thin film by laser irradiation

The authors report the electrical response measurements of an YBCO superconducting thin film to YAG laser light. The YBCO film used in this study is deposited by rf magnetron sputtering from a single YBa2Cu3Ox target onto MgO substrate and the film thickness is about 0.5 μ Tc of the film is 79 K. The film sample is mounted in vacuum in a cryostat. A pulsed Q-switched Nd:YAG laser (wavelength 1.06 μm, full width at half maximum 10 ns) is used to irradiate the film surface in the usual four-probe arrangement. The voltage signals of the sample provided with a dc bias current of 100 mA are measured with an oscilloscope at a laser energy of about 1.7 mJ/cm2 for various initial temperatures