Edge Contamination, Bulk Disorder, Flux Front Roughening, and Multiscaling in Type II Superconducting Thin Films

Abstract

We have investigated the effect of different types of disorder on the propagation, roughness, and scaling properties of magnetic flux fronts in a type II superconductor. A progression from the usual (Kardar–Parisi–Zhang-type) scaling to multiscaling is observed as the disorder strength is increased. A hierarchy of disorder strengths is established for YBa 2 Cu 3 O 7 − δ thin films. The results cast light on the physical origin of the roughening of flux fronts, and they are of interest for the design and elimination of flux noise in microscopic superconducting thin-film devices.

Keywords

• type II superconductivity
• vortex matter
• flux pinning
• critical current density
• flux penetration
• critical state
• disorder
• irradiation
• roughening of elastic manifolds
• nonlinear diffusion