Crystallization Induced by Laser Irradiation in Ba-Y-Cu-O Superconducting Films Prepared by Laser Ablation

Abstract

Ba₂YCu₃O _x superconducting films were prepared by laser ablation with some newly developed laser processing techniques. First, we revealed that a rapid postannealing by laser irradiation converts an amorphous film to a crystallized superconducting one. Second, we tried the in situ preparation without a high-temperature postannealing. To reduce the substrate temperatures T _s for the film preparation, we examined the effect of the laser irradiation on the growing film surface. We found that in situ excimer laser irradiation of the growing film surface improves the superconducting properties and the surface morphology of the films prepared at a relatively low T _s. This improvement is brought about mainly by the enhancement of the film crystallization, rather than by providing additional oxygen atoms to the film.