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

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 conditio ns on alpha. Film properties which were analyzed include the film thickness , the droplet density, the critical temperature T-c0, the surface morpholog y as seen by scanning electron microscopy (SEM) as well as crystal quality measured by Rutherford backscattering spectroscopy. With increasing angle a lpha 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.