Anisotropic microwave absorption and dc resistance in magnetic fields of granular superconducting aluminum films

The microwave absorption and critical resistive behaviour of superconducting granular aluminum films, which are metallic in their normal state, have been examined. Microwave absorption is appreciable in these films and can be accounted for by dissipation of flux motion. Perpendicular flux readily penetrates the film while parallel flux enters more gradually. Film resistance is sensitive to field direction because of the perpendicular demagnetizing field, weak pinning of perpendicular flux and inhibited nucleation of parallel fluxons. © 1989.