Drift of suspended ferromagnetic particles due to the Magnus effect

TL;DR

This paper investigates how ferromagnetic particles suspended in a viscous fluid drift under a time-periodic force and magnetic field, driven by the Magnus effect, with potential applications in particle separation.

Contribution

It introduces a minimal model to analyze the drift of ferromagnetic particles due to the Magnus effect, including analytical and numerical calculations of drift velocities.

Findings

Particles exhibit unidirectional and bidirectional drift.

Drift direction depends on core-shell ratio.

Bidirectional drift can be used for particle separation.

Abstract

A minimal system of equations is introduced and applied to study the drift motion of ferromagnetic particles suspended in a viscous fluid and subjected to a time-periodic driving force and a nonuniformly rotating magnetic field. It is demonstrated that the synchronized translational and rotational oscillations of these particles are accompanied by their drift in a preferred direction, which occurs under the action of the Magnus force. We calculate both analytically and numerically the drift velocity of particles characterized by single-domain cores and nonmagnetic shells and show that there are two types of drift, unidirectional and bidirectional, which can be realized in suspensions composed of particles with different core-shell ratios. The possibility of using the effect of bidirectional drift for the separation of core-shell particles in suspensions is also discussed.