All MgB₂ Josephson Junctions with Amorphous Boron Barriers

抄録

All MgB₂ Josephson junctions with amorphous boron barriers have been fabricated on C-plane sapphire substrates by using a co-evaporation method. The junctions showed Josephson currents and the nonlinear current-voltage characteristics which seem to reflect the superconducting energy gap. The critical current was observed when the thickness of the amorphous boron was in the range of 5nm to 20nm. The critical current density was estimated to be 0.4A/cm² to 450A/cm². By observing he temperature dependence of the critical current we found that the junction had a critical temperature of 10K and a normal layer in its barrier structure.