Experimental test of the self-organized criticality of vortices in superconductors

Abstract

Magneto-optical studies of the vortex dynamics in Nb films reveal stochastic jumps of flux bundles forming a rough penetration front. The scaling analysis of the width, correlation function, and the length of flux profiles behind the front retrieves the roughness exponents and Housdorff dimension characterizing the self-organized critical state. The exponents correspond to (1+1)-dimensional nonlinear diffusion in systems with quenched disorder and long-range correlations. The power spectra of the profiles confirm the self-affine character of the dynamically formed critical state.