Rectification of vortex motion in a circular ratchet channel

N. S. Lin, T. W. Heitmann, K. Yu, Britton Plourde, V. R. Misko

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

We study the dynamics of vortices in an asymmetric (i.e., consisting of triangular cells) ring channel driven by an external ac current I in a Corbino setup. The asymmetric potential rectifies the motion of vortices and induces a net vortex flow without any unbiased external drive, i.e., the ratchet effect. We show that the net flow of vortices strongly depends on vortex density and frequency of the driving current. Depending on the density, we distinguish a "single-vortex" rectification regime (for low density, when each vortex is rectified individually) determined by the potential-energy landscape inside each cell of the channel (i.e., "hard" and "easy" directions) and "multi-vortex," or "collective," rectification (high-density case) when the inter-vortex interaction becomes important. We analyze the average angular velocity ω of vortices as a function of I and study commensurability effects between the numbers of vortices and cells in the channel and the role of frequency of the applied ac current. We have shown that the commensurability effect results in a stepwise ω-I curve. Besides the "integer" steps, i.e., the large steps found in the single-vortex case, we also found "fractional" steps corresponding to fractional ratios between the numbers of vortices and triangular cells. We have performed preliminary measurements on a device containing a single weak-pinning circular ratchet channel in a Corbino geometry and observed a substantial asymmetric vortex response.

Original languageEnglish (US)
Article number144511
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume84
Issue number14
DOIs
StatePublished - Oct 7 2011

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rectification
Vortex flow
vortices
cells
flow nets
Angular velocity
angular velocity
Potential energy
integers
potential energy

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

Cite this

Rectification of vortex motion in a circular ratchet channel. / Lin, N. S.; Heitmann, T. W.; Yu, K.; Plourde, Britton; Misko, V. R.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 84, No. 14, 144511, 07.10.2011.

Research output: Contribution to journalArticle

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