A Hybrid Brownian Dynamics-kinetic Monte Carlo Framework for Coupled Magnetic and Rotational Dynamics of Nanoparticles
Abstract
Simulating the coupled magnetic and rotational dynamics of suspended magnetic nanoparticles (MNPs) over experimentally relevant timescales remains computationally demanding, particularly under low-frequency alternating magnetic fields. Here, we develop a hybrid Brownian Dynamics--kinetic Monte Carlo (BD--kMC) framework that combines thermally activated magnetic switching with particle rotation while retaining local fluctuations of the magnetic moment. These fluctuations are incorporated through Metropolis Monte Carlo (MC) sampling, allowing the moment to depart from the energy minima and thereby capturing the thermally averaged anisotropy torque that governs particle rotation. To preserve the distinction between local fluctuations and magnetic reversals, a barrier-trapping criterion confines MC trial moves to the current energy well, leaving thermally activated switching to the kMC process. For non-interacting single-domain MNPs, comparison with stochastic Landau--Lifshitz--Gilbert (LLG) simulations demonstrates agreement in the equilibrium torque and stationary easy-axis orientation, including the field-driven transition from predominantly perpendicular to parallel alignment. The resulting BD--kMC framework provides an efficient approach to coupled magnetic and Brownian Dynamics, reducing the computational cost of exploring the long timescales relevant to low-frequency magnetic applications.
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BibTeX
@misc{haq2026hybrid,
title = {{A Hybrid Brownian Dynamics-kinetic Monte Carlo Framework for Coupled Magnetic and Rotational Dynamics of Nanoparticles}},
author = {Siraj Ul Haq and Iago López-Vázquez and Kazuya Okada and Sergiu Ruta and Amira Páez-Rodríguez and Lucía Gutiérrez and Òscar Iglesias and David Serantes and Roy W. Chantrell},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.36102},
eprint = {2610.36102},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.36102},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A Hybrid Brownian Dynamics-kinetic Monte Carlo Framework for Coupled Magnetic and Rotational Dynamics of Nanoparticles
AU - Siraj Ul Haq
AU - Iago López-Vázquez
AU - Kazuya Okada
AU - Sergiu Ruta
AU - Amira Páez-Rodríguez
AU - Lucía Gutiérrez
AU - Òscar Iglesias
AU - David Serantes
AU - Roy W. Chantrell
PY - 2026
DA - 2026/10/26
PB - arXiv
DO - 10.48550/arxiv.2610.36102
UR - https://arxiv.org/abs/2610.36102
AB - Simulating the coupled magnetic and rotational dynamics of suspended magnetic nanoparticles (MNPs) over experimentally relevant timescales remains computationally demanding, particularly under low-frequency alternating magnetic fields. Here, we develop a hybrid Brownian Dynamics--kinetic Monte Carlo (BD--kMC) framework that combines thermally activated magnetic switching with particle rotation while retaining local fluctuations of the magnetic moment. These fluctuations are incorporated through Metropolis Monte Carlo (MC) sampling, allowing the moment to depart from the energy minima and thereby capturing the thermally averaged anisotropy torque that governs particle rotation. To preserve the distinction between local fluctuations and magnetic reversals, a barrier-trapping criterion confines MC trial moves to the current energy well, leaving thermally activated switching to the kMC process. For non-interacting single-domain MNPs, comparison with stochastic Landau--Lifshitz--Gilbert (LLG) simulations demonstrates agreement in the equilibrium torque and stationary easy-axis orientation, including the field-driven transition from predominantly perpendicular to parallel alignment. The resulting BD--kMC framework provides an efficient approach to coupled magnetic and Brownian Dynamics, reducing the computational cost of exploring the long timescales relevant to low-frequency magnetic applications.
ER -