Dynamical fluctuations in mode locking experiments on vortices moving through mesoscopic channels

TL;DR

This paper investigates vortex flow in mesoscopic channels using mode locking, revealing large voltage broadening and loss of coherence as the system approaches pure dc flow, indicating dynamical fluctuations.

Contribution

It introduces the application of mode locking to study vortex dynamics in mesoscopic channels and uncovers the nature of fluctuations near the transition to dc flow.

Findings

Large voltage broadening in mode locking signals.

Divergence of voltage width near pure dc flow.

Loss of temporal coherence in vortex motion.

Abstract

We have studied the flow properties of vortices driven through easy flow mesoscopic channels by means of the mode locking (ML) technique. We observe a ML jump with large voltage broadening in the real part of the rf-impedance. Upon approaching the pure dc flow by reducing the rf amplitude, the ML jump is smeared out via a divergence of the voltage width. This indicates a large spread in internal frequencies and lack of temporal coherence in the dc-driven state.