Implementation of superconductor-ferromagnet-superconductor pi-shifters in superconducting digital and quantum circuits

Interrupting a superconducting loop with a thin ferromagnetic film creates a so-called π-Josephson junction that shifts the phase of a current flowing in the loop by 180°. A demonstration of the use of π-junctions in a variety of device structures suggests they could enable the development of a new class of superconducting logic circuits.