Critical current and negative magnetoresistance of superconducting film with edge barrier
Theoretical Physics Department, Nizhny Novgorod University - Novgorod, Russia
Accepted: 18 December 2000
The field-dependent critical current and current-voltage characteristics are found within a generalized critical-state model that accounts for both surface barrier and bulk pinning as major irreversibility mechanisms in type-II superconductors. Calculations are made for an exactly solvable case of a thin-film superconductor taking into account the Ginzburg-Landau nonlinearity of the order-parameter equation. The shape of the current-voltage characteristics of the film is determined for arbitrary magnetic field. The nonmonotonous field dependence of the differential film resistivity is discovered, which is characterized by a negative magnetoresistance in a low-field region and by the Bardeen-Stephen-like behaviour in a high-field region.
PACS: 74.60.Ec – Mixed state, critical fields, and surface sheath
© EDP Sciences, 2001