Magnetoresistance measurements [1,2] on nano-scale loops of
La1.84Sr0.16CuO4, a high-temperature superconductor (Tc ~38 K), revealed
oscillations with a period of h/2e and amplitude larger by two orders of
magnitude than that expected from the Little-Parks effect. Unlike the
Little-Parks oscillations, which are caused by periodic changes in the
superconducting transition temperature, the oscillations we observe are
caused by periodic changes in the interaction between thermally-excited
moving vortices and the oscillating persistent current induced in the loops.
The enhanced amplitude of these oscillations may facilitate the search for
flux periodicities of h/e, as recently predicted for nanoscale loops of
superconductors with d-wave symmetry, or with a period of h/4e, as predicted
for superconductors that exhibit stripes.
[1] I. Sochnikov et al., Nature Nano. 5, 516 (2010).
[2] I. Sochnikov et al., PRB 82, 094513 (2010).