Dynamic trajectory analysis of superparamagnetic beads driven by on-chip micromagnets.

Journal Article

We investigate the non-linear dynamics of superparamagnetic beads moving around the periphery of patterned magnetic disks in the presence of an in-plane rotating magnetic field. Three different dynamical regimes are observed in experiments, including (1) phase-locked motion at low driving frequencies, (2) phase-slipping motion above the first critical frequency fc1, and (3) phase-insulated motion above the second critical frequency fc2. Experiments with Janus particles were used to confirm that the beads move by sliding rather than rolling. The rest of the experiments were conducted on spherical, isotropic magnetic beads, in which automated particle position tracking algorithms were used to analyze the bead dynamics. Experimental results in the phase-locked and phase-slipping regimes correlate well with numerical simulations. Additional assumptions are required to predict the onset of the phase-insulated regime, in which the beads are trapped in closed orbits; however, the origin of the phase-insulated state appears to result from local magnetization defects. These results indicate that these three dynamical states are universal properties of bead motion in non-uniform oscillators.

Full Text

Duke Authors

Cited Authors

  • Hu, X; Abedini-Nassab, R; Lim, B; Yang, Y; Howdyshell, M; Sooryakumar, R; Yellen, BB; Kim, C

Published Date

  • November 24, 2015

Published In

Volume / Issue

  • 118 / 20

Start / End Page

  • 203904 -

PubMed ID

  • 26648596

Pubmed Central ID

  • 26648596

Electronic International Standard Serial Number (EISSN)

  • 1089-7550

International Standard Serial Number (ISSN)

  • 0021-8979

Digital Object Identifier (DOI)

  • 10.1063/1.4936219


  • eng