The current-voltage characteristics and critical current versus magnetic field dependence of long 24 [001]-tilt YBa 2 Cu 3 O 7Àd bicrystal grain-boundary junctions are studied both experimentally and theoretically. For the opposite magnetic field directions, the flux-flow steps with significantly different height and slope are observed. It is demonstrated that the most probable reason of this discrepancy is recently predicted asymmetry of spatial bias current distribution due to crystallographic anisotropy of bicrystal substrates [

We carry out experimental and theoretical investigations into the effect of the vortex chain propagation on the current-voltage characteristics of YBa 2 Cu 3 O 7−δ (YBCO) long Josephson junctions. Samples of YBCO Josephson junctions, fabricated on 24°[001]-tilt bicrystal substrates, have been measured. The improved technology has allowed us to observe and study the asymmetry of the current-voltage characteristics with opposite magnetic fields (Revin et al 2012 J. Appl. Phys. 114 243903), which we believe occurs due to anisotropy of bicrystal substrates (Kupriyanov et al (2013 JETP Lett. 95 289)). Specifically, we examine the flux-flow resonant steps versus the external magnetic field, and study the differential resistance and its relation to oscillation power for opposite directions of vortex propagation.

The amplitudes of the first Shapiro steps for an external signal with frequencies of 72 and 265 GHz are measured as function of the temperature from 20 to 80 K for a 6 μm Josephson grain boundary junction fabricated by YBaCuO film deposition on an yttria-stabilized zirconia bicrystal substrate. Non-monotonic dependences of step heights for different external signal frequencies were found in the limit of a weak driving signal, with the maxima occurring at different points as function of the temperature. The step heights are in agreement with the calculations based on the resistively–capacitively shunted junction model and Bessel theory. The emergence of the receiving optima is explained by the mutual influence of the varying critical current and the characteristic frequency.