Measurement of the Vortex Pair Interaction Potential in a Type-II Superconductor

Abstract
We describe the first direct measurement of the pair interaction potential for magnetic flux lines in a type-II superconductor. Our approach relies on a quantitative analysis of Lorentz microscope images of vortices creeping through a superconducting thin film. Time-resolved vortex distributions imaged in this way reflect both the vortices' mutual interaction and also the influence of random pinning forces. These influences are isolated and quantified by adapting results from the theory of simple liquids.