Figure 1
The critical divergence of the relaxation time \(\tau (I)\) at the current-driven depinning transition (\(I_{c}\)). (a, c) I–V characteristics at 4.1 K in (a) 1.27 T and (c) 3.8 T on a linear-linear scale. Inset: I–V data plotted on a log–log scale. A vertical arrow and dashed line in each main panel and inset, respectively, indicate the depinning current \(I_{d}\) = 0.375 mA defined using a \(10^{-8}\) V criterion. Other lines are guide to the eye. (b, d) The critical divergence of \(\tau (I)\) at the I-driven depinning transition in (b) 1.27 T and (d) 3.8 T. The open and solid red circles represent \(\tau\) for \(I\le\) 0.37 mA and \(I\ge\) 0.39 mA, respectively, showing a power-law divergence at 0.375 ± 0.005 mA(\(\equiv I_{c}\)) from both sides, as marked with a vertical dashed line. Inset: \(\log {\tau }\) versus \(\log {|I-I_{c}|}\) in (b) 1.27 T and (d) 3.8 T, where symbols are the same as in the main panel. Both the dotted and full red lines indicate the power-law fits by \(\tau \propto |I-I_{c}|^{-\nu }\) with (b) \(\nu\) = 1.34 ± 0.13 and (d) \(\nu\) = 1.02 ± 0.15. The error bars in \(\tau\) mainly correspond to the fitting errors resulting from the uncertainty in determining a.
