Reversible Resistivity Control of Ba2YCu3O7-δ Thin Films by Laser Annealing

Abstract
Laser annealing of superconducting Ba2YCu3O7-δ (BYCO) thin films has been investigated by using a Nd:YAG cw laser. By laser irradiation at power densities higher than 1.4×105 W/cm2, superconducting polycrystalline films became amorphous and showed semiconductor-like temperature dependence on resistivity. The amorphization is apparently caused by a rapid quenching of molten BYCO after laser irradiation. The superconductivity of the film could be recovered by annealing the laser-irradiated film in a furnace. With this mask-free laser irradiation process, patterning of superconducting films can be achieved.