Segment of an inhomogeneous mesoscopic loop as a dc power source
  A dc voltage changed periodically with magnetic field is observed on segments of asymmetric aluminum loop without any external dc current at temperatures corresponded to superconducting transition. According to this experimental result a segment of the loop is a dc power source. A possibility of a persistent voltage on segments of an inhomogeneous normal metal mesoscopic loop follows from this result. 
S. V. Dubonos, V. I. Kuznetsov, and A. V. Nikulov
cond-mat.supr-con