Shape-dependent magnetic and microwave absorption properties of iron oxide nanocrystals

Liu, Xiang; Cao, Keyan; Chen, Yuanzhi; Ma, Yating; Zhang, Qinfu; Zeng, Deqian; Liu, Xiaolong; Wang, Laisen; Peng, Dong‐Liang

doi:10.1016/j.matchemphys.2017.02.012

Cited by 39 publications

(26 citation statements)

References 41 publications

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“…Moreover, owing to their electrical and magnetic properties [ [107] , [108] , [109] ]. Fe 3 O 4 particles have been incorporated into electrospun nanofibers aiming to develop lightweight microwave absorption absorber.…”

Section: Interactive Smart Fibers Produced By Electrospinningmentioning

confidence: 99%

A review of smart electrospun fibers toward textiles

Liu

Ding

et al. 2020

Composites Communications

137

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Section: Interactive Smart Fibers Produced By Electrospinningmentioning

confidence: 99%

A review of smart electrospun fibers toward textiles

Liu

Ding

et al. 2020

Composites Communications

137

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“…Magnetic losses are not included properly in SAR calculations of current dosimetric software packages. Magnetic losses may have 4 possible origins: a) relaxation due to the rotation of the magnetic moments (without rotation of the whole particle) -Neel relaxation, b) relaxation due to the rotation of the particle in the alternating field -Brownian relaxation, c) shifting of magnetic domain walls in multidomain materials -hysteresis loss, and d) generation of Foucault (eddy) currents in bulk materials or at centimetric scale (resistive heating when the magnetic flux is rapidly varying) [45][46][47][48]. The first 3 mechanisms of heat dissipation are detected mainly in nanometric dimensions and depend on size, shape, crystalline anisotropy, morphology, and degree of aggregation/agglomeration of the crystals.…”

Section: Limitations Of Present Radiofrequency Softwarementioning

confidence: 99%

“…Neglecting the effects of eddy currents in the GHz spectrum is completely inappropriate. An efficient and accurate modeling tool for multiphysics problems that encompasses electrodynamics and micromagnetics was proposed in [48]. Three major problems in modeling interactive micromagnetics and electromagnetic waves were solved using [48]: 1) coupling between Maxwell's equations and the LLG equation in every time step, 2) scale disparity of the multiphysics, 3) field discontinuity at material interfaces.…”

Section: Limitations Of Present Radiofrequency Softwarementioning

confidence: 99%

Magnetite Particle Presence in the Human Brain: A Computational Dosimetric Study to Emphasize the Need of a Complete Assessment of the Electromagnetic Power Deposition at 3.5 GHz

Vatamanu

Miclăuș

2021

Eng. Technol. Appl. Sci. Res.

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The growing evidence of increased magnetite nanoparticles (both endo- and exo-genic) in the human brain raises the importance of assessing the entire power deposition when electromagnetic waves at GHz frequencies propagate in such tissues. This frequency range corresponds to many popular portable communication devices that emit radiation close to a human's head. At these frequencies, the current dosimetric numerical codes can not accurately compute the magnetic losses part. This is due to the lack of an implemented computational algorithm based on solving the coupled Maxwell and Landau-Lifshitz-Gilbert equations, in the case of magneto-dielectrics, considering eddy currents losses and specific properties of magnetic sub-millimetric particles. This paper focuses on analyzing the limits and the inconsistencies when using commercial dosimetric numerical software to analyze the total absorbed power in brain models having ferrimagnetic content and being exposed to 3.5GHz electromagnetic waves. Magnetic losses computed using Polder’s permeability tensor as constitutive relation lead to unreliable results. However, using such software can provide a preliminary view of the electromagnetic impact of ultra- and super-high frequencies on magnetic-dielectric tissues.

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“…All of these depend on the size, shape, crystalline anisotropy, morphology and the degree of aggregation/agglomeration of nanoparticles [26][27][28][29][30][31][32][33][34]. It should be noted that, in the general case, a fourth mechanism is possible as well -the generation of Foucault (eddy) currents, consisting in resistive heating caused by a rapidly varying magnetic flux.…”

Section: Microscopic Dosimetry For Loss Determination In Magnetite Namentioning

confidence: 99%

Would the Human Brain Be Able to Erect Specific Effects Due to the Magnetic Field Component of an Uhf Field via Magnetite Nanoparticles?

Miclăuș¹,

Iftode²,

Miclaus³

2018

PIER M

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Abstract-In 2016 a study reported observing a concentration of magnetite nanocrystals in human brains, with four orders of magnitude larger than previously thought. In the context of magnetite's role and function inside the human brain not being properly understood, this development prompts a question concerning the impact that a significant magnetic near-field component, in the hundreds of MHz range, might have on power loss in tissues having ferrimagnetic properties. This article highlights the importance of thorough research on possible thermal and non-thermal effects that could be caused by the magnetic field component to which one could be exposed while using certain communication devices near or in front of the head. Furthermore, this article provides preliminary estimations of magnetic contribution to the specific absorption rate (SAR) of energy deposition in tissues, using two approaches -one based on existing research concerning magnetic hyperthermia, and the other one based on a simulation model that takes into account the magnetic properties of tissues. By simulating the propagation of a 440 MHz wave in a "magnetic" (as opposed to pure dielectric) brain, we observed changes of the SAR values, and, more importantly, superficial hot spots appeared at the surface of small magnetite particles, distributed in the homogenous brain.

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Shape-dependent magnetic and microwave absorption properties of iron oxide nanocrystals

Cited by 39 publications

References 41 publications

A review of smart electrospun fibers toward textiles

A review of smart electrospun fibers toward textiles

Magnetite Particle Presence in the Human Brain: A Computational Dosimetric Study to Emphasize the Need of a Complete Assessment of the Electromagnetic Power Deposition at 3.5 GHz

Would the Human Brain Be Able to Erect Specific Effects Due to the Magnetic Field Component of an Uhf Field via Magnetite Nanoparticles?

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