Hysteretic Josephson Junction Behavior of Ba1-xKxBiO3 Grain Boundary Junctions Using SrTiO3 Bicrystal Substrates

Abstract

We have fabricated Ba1-x Kx BiO3 artificial grain boundary junctions with low resistance on a SrTiO3 bicrystal substrate. These junctions show hysteretic junction behavior with a clear superconducting energy gap structure and Josephson current. The area resistance was low; it ranged from 5.2×10-8 to 2.0×10-5 Ω ·cm2. The I cR n product of the 20-µm-wide junction was 3.5 mV at 4.2 K. The gap voltage increased as the heater temperature increased and reached about 8 mV. A weak magnetic field applied normal to the substrate induced a Fraunhofer-type pattern.