Influence of target-substrate angle on properties of laser deposited YBa2Cu3O7-delta thin films and step-edge Josephson junctions

摘要

YBa2Cu3O7-delta (YBCO) thin films have been made by pulsed laser deposition (PLD) under variable angles alpha between target and substrate orientation. For several angles alpha the laser pulse energy E and the oxygen pressure p(O2) were varied to study the dependence, of optimal film growth conditions on alpha. Film properties which were analyzed include the film thickness, the droplet density, the critical temperature T-c0, the surface morphology as seen by scanning electron microscopy (SEM) as well as crystal quality measured by Rutherford backscattering spectroscopy. With increasing angle alpha we find a shift of the optimal growth conditions towards higher laser pulse energy. Step-edge Josephson junctions prepared from YBCO films which were deposited under different angles cu show a maximum product of critical current density and normal resistivity at alpha = 20-45 degrees. (C) 2000 Elsevier Science B.V. All rights reserved. [References: 16]