Heitmann T W, Yu K, Song C, DeFeo M P, Plourde B L T, Hesselberth M B S, Kes P H
Department of Physics, Syracuse University, Syracuse, New York 13244-1130, USA.
Rev Sci Instrum. 2008 Oct;79(10):103906. doi: 10.1063/1.3000683.
We have developed a picovoltmeter using a Nb dc superconducting quantum interference device for measuring the flux-flow voltage from a small number of vortices moving through a submicron weak-pinning superconducting channel. We have applied this picovoltmeter to measure the vortex response in a single channel arranged in a circle on a Corbino disk geometry. The circular channel allows the vortices to follow closed orbits without encountering any sample edges, thus eliminating the influence of entry barriers.
