Heights of microwave induced steps, temperature dependent supercurrent and other experimental observations in YBCO weak link

For YBCO bridges made of bulk samples, the authors have carefully measured the height of the microwave-induced steps as a function of applied microwave power and found, for Omega =hf/2eI/sub c/R=0.25, approximate agreement with the Bessel function dependence. The supercurrent versus temperature dependence follows the I/sub c/ varies as (1-T/T/sub c/) relationship quite closely at temperatures far from T/sub c/, while in the vicinity of T/sub c/ the deviation from it can be pronounced. For bridges made of YBCO thin films, the temperate-dependent supercurrent can be expressed as I/sub c/ varies as (1-T/T/sub c/)/sup 3/2/. Also discussed are some possible explanations of experimentally observed I-V curves which might be attributed to mechanisms such as self-heating and junctions in series.<
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