Improvement in Ba 1-x K x BiO 3 Grain Boundary Junctions by Ar + Beam Irradiation

To control the normal resistance of Ba 1- x K x BiO 3 (BKBO) artificial grain boundary junctions, the influence of Ar + beam irradiation on BKBO junctions on MgO (100) bicrystal substrates was investigated. Contrary to our expectation, the properties of all junctions were found to be improved. In the most marked changes, the critical current density increased from 2.3 kA/cm 2 to 31 kA/cm 2 , while the normalized junction resistivity decreased from 1.4 × 10 -6 Ω·cm 2 to 1.4 × 10 -7 Ω·cm 2 . No change was observed in the gap voltages and the critical current density of the BKBO films.