<title>Segment of inhomogeneous mesoscopic loop as a dc power source</title>

Abstract

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.

The Meissner effect puzzle and the quantum force in superconductor

“…The dc voltage oscillations V dc (Φ/Φ 0 ) ∝ I p (Φ/Φ 0 ) were observed already on the ring-halves with different sections s w > s n when the asymmetric ring is switched between superconducting and normal states by ac electrical current [13,14] or a noise [8,9,12,15]. These paradoxical observations of the circular electrical current I p flowing against the dc electrical field E = − ▽ V dc in one of the ring-halves can not be explained also without the quantum force.…”

“…Little and R. D. Parks [7] at measurements of the resistance of thin cylinder in the temperature region corresponding to its superconducting resistive transition. Later on, the quantum oscillations of the ring resistance ∆R ∝ I 2 p [8,9], its magnetic susceptibility ∆Φ Ip = LI p [10], the critical current I c (Φ/Φ 0 ) = I c0 − 2|I p (Φ/Φ 0 )| [11] and the dc voltage V dc (Φ/Φ 0 ) ∝ I p (Φ/Φ 0 ) measured on segments of asymmetric rings [8,9,[12][13][14][15] were observed.…”

Quantum Oscillations of the Critical Current of Asymmetric Aluminum Loops in Magnetic Field

“…Such quantum oscillations of the dc voltage were observed on segment of asymmetric aluminum loops [4,5] and much before on a double Josephson point contact [6]. The dc voltage V(Φ/Φ 0 ) observed near the critical temperature T c [4,6] can be induced by switching of the loop between superconducting states with different connectivity [7,8]. The quantum oscillations V(Φ/Φ 0 ) induced at lower temperatures by an external ac current [5] may by interpreted as a result of the rectification because of asymmetry of the current-voltage curves sign and value of which are periodical function of Φ.…”

“…According to an analogy with the conventional circular current a dc potential difference V(Φ/Φ 0 ) ∝ I p (Φ/Φ 0 ) ∝ <n>-Φ/Φ 0 may be expected to be observed on segments of asymmetric superconductor loop at R l > 0. Such quantum oscillations of the dc voltage were observed on segment of asymmetric aluminum loops [4,5] and much before on a double Josephson point contact [6]. The dc voltage V(Φ/Φ 0 ) observed near the critical temperature T c [4,6] can be induced by switching of the loop between superconducting states with different connectivity [7,8].…”

Langevin approach to the Porto system

“…• First, there is at present increasing evidence, both theoretical [10,11,12,13,14,15] and experimental [16,17,18] as well as combined one [19], in favor of potential violability of the Second law.…”