Nd:YAG laser irradiation of molecular-beam-epitaxy-deposited YBa2CU3O7-x superconducting thin films

Superconducting thin films of 123 compound were deposited on (100) single-crystalline SrTiO3 substrates using a molecular-beam-epitaxy system. Films were characterized by x-ray diffraction, scanning electron microscopy and compositional analysis using the EDAX technique. The films were irradiated by a 1.064 mu m wavelength Q-switched Nd:YAG laser of 20 ns pulse duration at 1.0 J cm-2/shot energy density. A systematic comparison of the film microstructure and compositional analysis before and after irradiation is presented here. Theoretical calculations based on a thermal model of laser heating to determine the surface-temperature rise of the film were performed using the finite-difference method. The film microstructure, showing fusion of grains, is attributed to the bolometric response of the whole film during 1.064 mu m laser irradiation. (author)