Meissner state in finite superconducting cylinders with uniform applied magnetic field

Abstract

We study the magnetic response of superconductors in the presence of low values of a uniform applied magnetic field. We report measurements of dc magnetization and ac magnetic susceptibility performed on niobium cylinders of different length-to-radius ratios, which show a dramatic enhancement of the initial magnetization for thin samples, due to the demagnetizing effects. The experimental results are analyzed by applying a model that calculates the magnetic response of the superconductor, taking into account the effects of the demagnetizing fields. We use the results of magnetization and current and field distributions of perfectly diamagnetic cylinders to discuss the physics of the demagnetizing effects in the Meissner state of type-II superconductors. © 2000 The American Physical Society.