Macroscopic Experiments on Magnetic Particle Dynamics

Three-dimensional rotation of magnetic particles in viscous media is a fundamental process underlying applications in magnetic hyperthermia, microfluidics, and soft robotics. However, direct observation and control of such dynamics at the microscale remain experimentally challenging due to imaging limitations and restricted tunability of particle properties. Here, we present a macroscopic analog platform that replicates microscale rotational behavior under controlled magnetic fields, enabling precise tuning of particle geometry, magnetic properties, and fluid environment. Using this system, we experimentally investigate and validate a theoretical model describing magnetic particle rotation, focusing on the critical angular frequency at which synchrony with the magnetic field is lost, the nature of three-dimensional precession in the asynchronous regime, and the influence of initial orientation on long-term dynamics. We further develop a dedicated image processing pipeline to extract high-resolution 3D rotational vectors from particle trajectories. This integrated approach offers a powerful scalable framework for simulating and optimizing magnetic particle-based technologies, with implications for targeted therapies, lab-on-a-chip devices, and dynamic material systems.