(Top) This is an artist’s concept, adapted from Ref. , showing part of the SQUID assembly—the field and pickup loops hovering over the gold rings of the sample. (Bottom) This figure (Fig. 3(a) from Ref. ) presents the difference between the averaged nonlinear responses, induced by the flux and measured by the SQUID, of two rings with sizeable responses, at a range of temperatures vs the applied external flux. Multiple data sets for some temperatures attest to the reproducibility of the results. An approximately fitted sinusoidal curve yields a period which is close to .