Large critical currents and current steps in shunted bicrystal Josephson junctions at liquid nitrogen temperatures
The amplitudes of the critical current and constant-voltage steps in shunted bicrystal Josephson junctions were explored as a function of the grain boundary type (symmetrical or asymmetrical), misorientation angle and thickness of films. Two new results were demonstrated. First, we found that for the given angles of to the junctions on symmetrical grain boundaries generated the highest critical current density . Second, the increase of superconducting film thickness up to allowed us to measure the first current step height of 1 mA and 2 mA in high- junctions operated at 80 K and 50 K respectively. Simulations with a wide-junction model have shown that the maximal current step amplitude in large critical current bicrystal junctions is controlled by a self-field effect.
Document Type: Miscellaneous
Institut für Schicht- und Ionentechnik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
Physikalische Fakultät der Technischen Universität München, 85748 Garching, Germany
Publication date: July 1, 1998