The effect of bias current asymmetry on the flux-flow steps in the grain boundary YBaCuO long Josephson junctions

length of the junctions l along the grain boundary was 350lm and the thickness was 0.3lm. The samples were mounted into the pulse tube PT-410 cryostat and characterized with the precise low-noise current source by standard 4-probe technique. The junctions had resistively shunted-junction like I–V curves at temperatures up to 80K. The junctions were very long since their lengths are much larger than the Josephson penetration depth