Vortex lattice dynamics in a-NbGe detected by mode-locking experiments

TL;DR

This paper investigates vortex lattice dynamics in a superconducting a-NbGe film using mode-locking experiments, revealing how vortex motion responds to rf and dc drives and confirming theoretical models of elastic lattice behavior.

Contribution

It provides experimental evidence of vortex lattice mode-locking in a-NbGe, demonstrating the expected voltage scaling and Bessel function dependence of the current step width.

Findings

ML voltage scales as $V ightarrow f\, ext{sqrt}(B)$

ML current step width follows a squared Bessel function dependence on rf-amplitude

Vortex lattice exhibits elastic motion through a random potential

Abstract

We observed mode-locking (ML) of rf-dc driven vortex arrays in a superconducting weak pinning a-NbGe film. The ML voltage shows the expected scaling $V\propto f\sqrt{B}$ with $f$ the rf-frequency and $B$ the magnetic field. For large dc-velocity (corresponding to a large ML frequency), the ML current step width exhibits a squared Bessel function dependence on the rf-amplitude as predicted for ML of a lattice moving elastically through a random potential.