Cross-talk effects in superconductor–insulator–normal-metal trilayers

We have observed a ``cross-talk'' effect in structures composed of two metal films, at least one of which is a superconductor, S, separated by a thin insulating layer. A current was passed through one film and the voltage induced in the other, V, was monitored. While V was negligibly small when film S was either normal or superconducting, V exhibited a peak in the immediate vicinity of the normal-to-superconducting transition. This effect was found to be nonreciprocal, as the sign of V depended on which film carried the current.