Transverse Commensurability Effect for Vortices in Periodic Pinning Arrays

TL;DR

This paper uses simulations to reveal a new transverse commensurability effect in vortex motion through periodic pinning arrays, showing enhanced depinning forces and novel dynamical states.

Contribution

It introduces a new type of commensurability effect for vortices under combined longitudinal and transverse drives in periodic pinning arrays, with significant implications for vortex dynamics.

Findings

Broad maxima in transverse depinning force at non-matching fields

Formation of evenly spaced moving vortex rows between pinning sites

Transverse depinning force can exceed longitudinal force by over ten times

Abstract

Using computer simulations, we demonstrate a new type of commensurability that occurs for vortices moving longitudinally through periodic pinning arrays in the presence of an additional transverse driving force. As a function of vortex density, there is a series of broad maxima in the transverse critical depinning force that do not fall at the matching fields where the number of vortices equals an integer multiple of the number of pinning sites. The commensurability effects are associated with dynamical states in which evenly spaced structures consisting of one or more moving rows of vortices form between rows of pinning sites. Remarkably, the critical transverse depinning force can be more than an order of magnitude larger than the longitudinal depinning force.