Modeling of Thermal Magnetic Fluctuations in Nanoparticle Enhanced Magnetic Resonance Detection

We present a systematic numerical modeling investigation of magnetization dynamics and thermal magnetic moment fluctuations of single magnetic domain nanoparticles in a configuration applicable to enhancing inductive magnetic resonance detection signal to noise ratio (SNR). Previous proposals for or...

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Bibliographic Details
Published in:arXiv.org 2021-01
Main Authors: Kaisar, Tahmid, Md Mahadi Rajib, ElBidweihy, Hatem, Barbic, Mladen, Atulasimha, Jayasimha
Format: Article
Language:English
Subjects:
Broadband
Coils
Configurations
Magnetic domains
Magnetic flux
Magnetic moments
Magnetic resonance imaging
Magnetic variations
Magnetism
Magnetization
Mathematical models
Nanoparticles
Noise
Scanners
Shape effects
Signal to noise ratio
Thermal noise
Thermal simulation
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Summary:We present a systematic numerical modeling investigation of magnetization dynamics and thermal magnetic moment fluctuations of single magnetic domain nanoparticles in a configuration applicable to enhancing inductive magnetic resonance detection signal to noise ratio (SNR). Previous proposals for oriented anisotropic single magnetic domain nanoparticle amplification of magnetic flux in MRI coil focused only on the coil pick-up voltage signal enhancement. Here we extend the analysis to the numerical evaluation of the SNR by modeling the inherent thermal magnetic noise introduced into the detection coil by the insertion of such anisotropic nanoparticle-filled coil core. We utilize the Landau-Lifshitz-Gilbert equation under the Stoner-Wohlfarth single magnetic domain (macrospin) assumption to simulate the magnetization dynamics in such nanoparticles due to AC drive field as well as thermal noise. These simulations are used to evaluate the nanoparticle configurations and shape effects on enhancing SNR. Finally, we explore the effect of narrow band filtering of the broadband magnetic moment thermal fluctuation noise on the SNR. Our results provide the impetus for relatively simple modifications to existing MRI systems for achieving enhanced detection SNR in scanners with modest polarizing magnetic fields.
ISSN:2331-8422
DOI:10.48550/arxiv.2101.04649