Macroscopic emulation of microscopic magnetic particle systems

Abstract

In this work we show that macroscopic experiments can be used to investigate microscopic systems. Such macroscopic experiments enable testing the assumptions and results obtained by theoretical considerations or simulations that can not be obtained under microscope (e.g., the orientation of a spherical particle). To emulate the dynamics of a single hematite cube immersed in water and subjected to a rotating magnetic field, a cubic magnet is firmly positioned in a 3D printed superball shell. The dimensionless parameters of the microscopic and macroscopic systems can be equalized by using a glycerol-water mixture instead of water as well as by the material and infill of the 3D printed shell. The pose of the superball is tracked using ArUco stickers which act as fiducial markers. It was found that there is a qualitative agreement between the macroscopic experiments and theoretical predictions. However, the reduced thermal effects in the macroscopic experiments lead to an increase in friction between the superball and the surface, thus shifting the critical frequency of the system. Since the shell is 3D printed, the given method can be extended to any shape and magnetization orientation.