Current-driven vortex dynamics at zero field in thick and thin films probed by voltage noise

We have measured current (I)-induced voltage (V) noise S-V of thick and thin amorphous Mo-x,Si1-x films with different transition temperatures T-c, but with similar critical current densities, to study vortex dynamics driven by I at zero field below T-c. Origin of noise is due to density fluctuations of thermally created free vortices and antivortices in the presence of I. With increasing temperature T, S-V/V shows a decrease and tends to zero near T-c, where S-V/V for the thick and thin films follows the single scaling functions expressed as S-V/V = A(1 - T/T-c)(n) (n approximate to 5-6) with large and small values of A, respectively. This means that the physical mechanism responsible for the T dependence of noise (or vortex-density fluctuations) for the thick and thin films is qualitatively similar, but quantitatively dominated by the dimensionality.