We discuss the microwave energy losses in superconductors in the critical state. The field-induced variations of the surface resistance are determined, in the framework of the Coffey and Clem model, by taking into account the distribution of the vortex magnetic field inside the sample. It is...

We study flux penetration in a disordered type II superconductor by simulations of interacting vortices, using a Monte-Carlo method for vortex nucleation. Our results show that a detailed description of the nucleation process yields a correction to the scaling laws usually associated with flux...

We present ac susceptibility measurements performed on (K, Ba)BiO<Subscript>3</Subscript>single crystals with different geometries: thick films, bars and hollow cylinders. We show that the h <Subscript>ac</Subscript> dependence of the real (χ′) and imaginary (χ′) parts of the ac susceptibility is in very good agreement with Brandt’s...</subscript></subscript>