Flux trapping and paramagnetic effects in superconducting thin films: The role of de Gennes boundary conditions

In the framework of the nonlinear time dependent Ginzburg–Landau (TDGL) equations we study the properties of a mesoscopic superconducting film with both surfaces in contact with different materials, whose properties are taken into account by de Gennes boundary conditions via the extrapolation length b. The vortex dynamics, the magnetization curves, vortex number and the modulus of the order parameter are studied as a function of the parameter b, which covers a broad range of positive and negative values (including the special cases b=0 and b→∞), the external magnetic field He and the temperature. We find that field cooled paramagnetic states, caused by flux compression, depends strongly on b and can be completely suppressed for low enough b values.