Thermopower of mesoscopic normal-metal/superconductor heterostructures

Measurements of micron-size doubly connected normal-metal/superconductor (N S) heterostructures show a thermoelectric response which oscillates as a fu nction of magnetic field, with a fundamental period corresponding to one fl ux quantum h/2e through the area of the loop. The oscillations of the therm opower are either symmetric or antisymmetric with respect to magnetic field , depending on the topology of the sample. The temperature dependence of th e amplitude of the oscillations shows a minimum at a temperature of 0.14 K, although this nonmonotonic behavior does not appear to be related to the r eentrance effect recently observed in the electrical transport properties o f NS structures.