Thermopower of Mesoscopic Normal-metal/Superconductor Heterostructures

Measurements of micron-size doubly connected normal-Metal/superconductor (NS) heterostructures show athermoelectric response which oscillates as a function ofmagnetic field, with a fundamental period corresponding to oneflux quantum h/2e through the area of the loop. Theoscillations of the thermopower are either symmetric orantisymmetric with respect to magnetic field, depending on thetopology of the sample. The temperature dependence of theamplitude of the oscillations shows a minimum at a temperatureof 0.14 K, although this nonmonotonic behavior doesnot appear to be related to the reentrance effect recentlyobserved in the electrical transport properties of NSstructures.