Magnetoresistance sign change in superconducting films: the role of an edge barrier

The resistive characteristics of pin-free type-II superconductors with an edge barrier are investigated. Analysis is based on a model system consisting of an infinitely long strip of finite width W and thickness d≪W. The current–voltage characteristics and magnetoresistance R(H) of the sample are calculated by numerical solution of the Maxwell–London equations, considered in the framework of a hydrodynamic description. It is found that the positive magnetoresistance (dR∕dH>0) that exists at low values of the transport current I I*. The sign change of the magnetoresistance is explained by a change of the dominant mechanism of energy dissipation in the film (i.e., a transition from viscous losses to annihilation losses). It is shown that the presence of weak magnetic flux pinning does not alter the behavior of R(H).