Nonmonotonous temperature dependence of Shapiro steps in YBCO grain boundary junctions

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

[学科分类] 环境监测和分析

[关键词] characteristic frequency;Shapiro steps;temperature dependence;YBaCuO Josephson junction