Inductive response of double sided superconductor film

Abstract

The possibility of obtaining penetration depth measurement for double sided superconductor film by using two-coil method is investigated. The simulation of screening current density distribution in both layers of film and the inductance of pick-up coil are made. The screening current density of lower film layer, the one farther away from the drive coil than upper film layer due to a substrate with thickness 0.5 mm, is approximately 1000 times smaller than that of the upper layer. The inductance of pick-up coil strongly depends on the penetration depth of upper layer only. In particular, its dependence on the penetration depth of lower layer is negligibly small when drive coil and pick-up coil are positioned at the same side of the film. Therefore, the penetration depth of each film layer can be determined by two separate measurements, one measurement for each side.