Direct investigations of the superconducting surface sheath and nonlocal electrodynamics by polarized neutron reflections.

Abstract

Using a very direct probe of surface magnetism, i.e., polarized neutron reflections, the penetration of a magnetic field into low-\ensuremath{\kappa} superconductors has been shown to be inadequately quantitatively described by the local Ginzburg-Landau (GL) theory. In addition, the existence of the surface sheath of superconductivity has been clearly and directly shown by using this probe on the diamagnetic surface sheath. In this case, numerical calculations based on the local GL theory are shown to provide a useful estimate of the size of the diamagnetism.