Second harmonics and compensation effect in ceramic superconductors

The nonlinear ac susceptibility and the compensation effect observed in ceramic superconductors which show the paramagnetic Meissner effect are studied by the Monte Carlo simulations on a three dimensional lattice model of the Josephson array with finite self-conductance. Our study is based on the possible existence of the chiral glass phase in these materials. In agreement with experiments, the compensation effect is demonstrated to be present in d-wave superconductors but not in the s-wave ones. (author)