A possibility of persistent voltage observation in a system of   asymmetric superconducting rings
  A possibility to observe the persistent voltage in a superconducting ring of different widths of the arms is experimentally investigated. It was earlier found that switching of the arms between superconducting and normal states by ac current induces the dc voltage oscillation in magnetic field with a period corresponding to the flux quantum inside the ring. We use systems with a large number of asymmetric rings connected in series in order to investigate the possibility to observe this quantum phenomenon near the superconducting transition where thermal fluctuations switch ring segments without external influence and the persistent current is much smaller than in the superconducting state. 
A. A. Burlakov, V. L. Gurtovoi, A. I. Ilin, A. V. Nikulov, V. A. Tulin
cond-mat.supr-con cond-mat.mes-hall