Characteristics of a free-standing superconducting nanobridge with an integrated heater fabricated using a self-aligned technique

We report on a novel method of controlling the supercurrent flow in a super conducting weaklink. We have fabricated a free-standing superconducting nan obridge with an integrated NiCr heater. This NiCr layer acts as a self-alig ned mask for reactive ion etching and also as the normal metal heating elem ent of the nanobridge. The heater is used to control the critical current o f the superconducting weaklink part of the the nanobridge; the free-standin g nature of the nanobridge reduces the heater power required. We discuss th e dependence of the current-voltage characteristics of the superconducting weaklink on heater current. This device has advantages over existing contro llable weaklink devices. (C) 1999 American Vacuum Society. [S0734-211X(99)0 6406-9].