Nucleation of superconductivity in finite metallic multilayers: Effect of the symmetry

摘要

The influence of the finite dimensions of superconducting metallic multilayers on H-T phase diagram is studied. It is established that the geometrical symmetry of the samples determines crucially the H_(c2‖)(T) dependencies. For samples where the symmetry plane is in the middle of the superconducting layer the H_(c2‖) values are, for temperatures close to T_c , larger than the H_(c2‖) values of the samples for which the symmetry plane lies in the middle of the normal layer. The results are analysed on the basis of the Ginzburg-Landau approach and are explained by considering the different symmetry of the wave function describing the system. The experimental results are in good agreement with the elaborated model, which takes into account the actual symmetry of the samples.