High-Tc superconducting integrated circuit - A dc SQUID with input coil

A high transition temperature superconducting integrated circuit consisting of a dc SQUID and an input coupling coil has been fabricated. The purpose is to ascertain the generic problems associated with constructing a high-Tc circuit as well as to fabricate a high performance dc SQUID. The superconductor used for both the SQUID and the input coil is Nb3SN, which must be deposited at 800 C. The insulator separating SQUID and input coil maintains its integrity at this elevated temperature. A hole in the insulator permits contact to the innermost winding of the coil. This contact has been achieved without significant degradation of the superconductivity. Consequently, the device operates over a wide temperature range, from below 4.2 K to near Tc.