Possibility of persistent voltage observation in a system of asymmetric superconducting rings

The possibility of observing persistent voltage in superconducting rings of different arm widths is experimentally investigated. It was previously found that switching of the arms between superconducting and normal states by an AC current induces DC voltage oscillation in the magnetic field with a period corresponding to the flux quantum inside the ring. We used systems with a large number of asymmetric rings connected in series to investigate the possibility of observing this quantum phenomenon near the superconducting transition, where thermal fluctuations lead to switching of ring segments without an external influence and the persistent current is much smaller than in the superconducting state.

► A possibility to observe the persistent voltage is investigated experimentally.
► The persistent voltage is a DC voltage observed at thermodynamic equilibrium.
► It oscillates in magnetic field like the persistent current in superconducting ring.
► The period of the oscillations corresponds to the flux quantum inside the ring.
► The quantum oscillations of the DC voltage were observed on asymmetric rings.