Characteristics of the switching in a superconducting Y-Ba-Cu-O thin film by laser irradiation

Radiation-induced switching of a Y-Ba-Cu-O thin film sample is studied using a 1.06 µm pulsed Q-switched Nd:YAG laser with a duration of 10 ns. The results of the switching from the super- to normal conducting states in our sample caused by laser irradiation are attributed to a bolometric effect, i.e., heating of the sample by radiation. The response time of the switching is less than 30 ns and it almost agrees with the relaxation time of the thermal conduction in the film. Using a simple model assuming uniform distribution of energy through the film thickness, the specific heat of the film is also estimated and a clear jump in the specific heat at the critical temperature is shown.