Critical current of a high <i>Tc</i> Josephson grain boundary junction in high magnetic field

Abstract

The critical current (Ic) of YBa2Cu3O7−δ grain boundary Josephson junctions was measured up to magnetic fields of 5 T. Magnetic field history dependent Ic values were observed even after correction for self-field effects stemming from hysteretic shielding currents in the grain adjacent to the boundary. A novel feature observed is an anomalous increase in Ic in high magnetic fields of several Telsa.