Thermal Stoner-Wohlfarth model for magnetodynamics of single domain nanoparticles

Author(s)
Deniz Mostarac, Andrey A. Kuznetsov, Santiago Helbig, Claas Abert, Pedro A. Sánchez, Dieter Suess, Sofia S. Kantorovich
Abstract

We present the thermal Stoner-Wohlfarth (tSW) model and apply it in the context of molecular dynamics simulations. The model is validated against an ensemble of immobilized, randomly oriented uniaxial particles (solid superparamagnet) and a classical dilute ferrofluid for different combinations of anisotropy strength and magnetic field/moment coupling, at a fixed temperature. We compare analytical and simulation results to quantify the viability of the tSW model in reproducing the equilibrium properties (with and without dipole-dipole interactions) and dynamic properties (without dipole-dipole interactions) of magnetic soft matter systems. We show that if the anisotropy of a particle is more than five times higher than the thermal fluctuations, the tSW model is applicable and efficient. This approach allows one to consider the interplay between Néel and Brownian relaxation, often neglected in the fixed point-dipole representation-based magnetic soft matter theoretical investigations.

Organisation(s)
Computational and Soft Matter Physics, Physics of Functional Materials
External organisation(s)
Sapienza University of Rome, Delft University of Technology
Journal
Physical Review B
Volume
111
No. of pages
14
ISSN
2469-9950
DOI
https://doi.org/10.48550/arXiv.2408.06136
Publication date
01-2025
Peer reviewed
Yes
Austrian Fields of Science 2012
103043 Computational physics, 103015 Condensed matter
ASJC Scopus subject areas
Electronic, Optical and Magnetic Materials, Condensed Matter Physics
Portal url
https://ucrisportal.univie.ac.at/en/publications/e7233f47-48dd-4f7d-9424-2dd09b82dd8e