Experimental Test of Strong Pinning and Creep in Current-Voltage Characteristics of Type-II Superconductors

Pinning and creep determine the current-voltage characteristics of a type-II superconductor and thereby its potential for technological applications. The recent development of strong pinning theory provides us with a tool to assess a superconductor's electric properties in a quantitative way. Motivated by the observation of typical excess-current characteristics and field scaling of critical currents, here we analyze current-voltage characteristics measured on 2H-NbSe₂ and α-MoGe type-II superconductors within the setting provided by strong pinning theory. The experimentally observed shift and rounding of the voltage onset is consistent with the predictions of strong pinning in the presence of thermal fluctuations. We find the underlying parameters determining pinning and creep and discuss their consistency.