Rolling at right angles : Magnetic anisotropy enables dual-anisotropic active matter

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Fitzgerald, Eavan and Clavaud, Cécile and Das, Debasish and Lenton, Isaac C. D. and Waitukaitis, Scott R. (2025) Rolling at right angles : Magnetic anisotropy enables dual-anisotropic active matter. Physical Review E, 112 (6). 065418. ISSN 2470-0053 (https://doi.org/10.1103/1ss8-31rb)

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Abstract

We report on an experimental active matter system with motion restricted to four cardinal directions. Our particles are magnetite-doped colloidal spheres driven by the Quincke electrorotational instability. The absence of a magnetic field ( | B | = 0 ) leads to circular trajectories interspersed with short spontaneous runs. Intermediate fields ( | B | ≲ 20 mT ) linearize the motion along the axis perpendicular to B . At high magnetic fields, we observe the surprising emergence of a second, distinct linearization along the axis parallel to B . With numerical simulations, we show that this behavior can be explained by anisotropic magnetic susceptibility.

ORCID iDs

Fitzgerald, Eavan, Clavaud, Cécile, Das, Debasish ORCID logoORCID: https://orcid.org/0000-0003-2365-4720, Lenton, Isaac C. D. and Waitukaitis, Scott R.;
  • Item type:Article
    ID code:95120
    Dates:
    Date
    Event
    12 December 2025
    Published
    12 November 2025
    Accepted
    Subjects:Science > Physics
    Department:Faculty of Science > Mathematics and Statistics
    Depositing user: Pure Administrator
    Date deposited:05 Jan 2026 13:37
    Last modified:06 Jan 2026 08:12
    URI:https://strathprints.strath.ac.uk/id/eprint/95120
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