Effects of target microstructure on pulsed laser deposited YBa2Cu3O7-delta thin films

Abstract

Superconducting YBa2Cu3O7-delta thin films were prepared by pulsed laser deposition using two targets; one was fabricated by solid-state sintering (SSS) and the other was fabricated by modified melt-textured growth (MTG). Microstructures of the targets and the films were investigated using X-ray diffraction and scanning electron microscopy. Also, superconducting properties of the films were examined by electrical measurements. When compared with SSS targets, MTG targets showed a denser microstructure consisting of larger grains, and the surfaces of MTG targets were less modified with the cumulative laser incidence. The films deposited from MTG targets showed better-aligned c-axis orientation, a higher density microstructure, and exhibited enhanced superconducting properties as compared to the films prepared from SSS targets. These results were ascribed to higher kinetic energies and an improved uniformity of the vapor species ejected from MTG targets. (C) 2000 published by Elsevier Science S.A. All rights reserved.