Surface Density of Normal Metal in the Intermediate State of Superconducting Aluminum

Abstract

Surface-impedance measurements have been made at 0.5 MHz on the intermediate state of aluminum and indicate an increased fraction of normal metal near the surface as compared with the bulk. This result confirms Landau's prediction of the surface structure in the intermediate state and suggests a similar interpretation for Pippard's early observation of the surface resistance of tin at 10 GHz. Surface-impedance techniques are thus seen to provide accurate information on domain broadening near the surface, and to corroborate the effective-field reduction there suggested qualitatively by bismuth-probe and magneto-optic methods.