Abstract
GdBa_2Cu_3O_y superconducting thin films show a high critical current density when the crystal grains are oriented in all directions. In this study we investigated the influence of film growth factors on the crystal orientation of the thin films during the film formation by a pulsed laser deposition technique. Substrate temperature and the oxygen pressure were varied from 680℃ to 800℃ and from 0.1Torr to 1.0Torr, respectively. It was found that the c-axis orientation was dependent of the substrate temperature, in particular; the films had highest proportions of c-axis grains at 760℃. Proportions of a-axis of the films increased at lower temperature and the oriented films cannot be obtained at high temperature. In addition it was shown that a-and-b-axes orientations were found dependent of oxygen pressure; the films formed at 0.1Torr and 0.4Torr aligned in-plane. The condition of achieving highest degrees of orientation is 760℃ and low oxygen pressure.
