Dynamic roughening of the magnetic flux landscape in [formula omitted

Abstract

We study the magnetic flux landscape in YBa 2 Cu 3 O 7 - x thin films as a two dimensional rough surface. The vortex density in the superconductor forms a self-affine structure in both space and time. It is characterized by a roughness exponent α = 0.76 ( 3 ) and a growth exponent β = 0.57 ( 6 ) . The roughening is caused by flux avalanches in a self-organized critical state, which is formed in the vortex matter of the superconductor. We discuss our results in the context of other roughening systems in the presence of quenched disorder.