Heating ability of elongated magnetic nanoparticles

Low-frequency hysteresis loops and specific absorption rate (SAR) of various assemblies of elongated spheroidal magnetite nanoparticles have been calculated for a range of particle semiaxis ratios a/b = 1.0–3.0. The SAR of a dilute randomly oriented assembly of magnetite nanoparticles in an alternating magnetic field of moderate frequency, f = 300 kHz, and amplitude H0 = 100–200 Oe is shown to decrease significantly with an increase in the aspect ratio of nanoparticles. In addition, there is a narrowing and shift of the intervals of optimal particle diameters towards smaller particle sizes. However, the orientation of a dilute assembly of elongated nanoparticles in a magnetic field leads to an almost twofold increase in SAR at the same frequency and amplitude of the alternating magnetic field, the range of optimal particle diameters remaining unchanged. The effect of the magneto-dipole interaction on the SAR of a dilute assembly of oriented clusters of elongated magnetite nanoparticles has also been investigated depending on the volume fraction of nanoparticles in a cluster. It has been found that the SAR of the assembly of oriented clusters decreases by approximately an order of magnitude with an increase in the volume fraction of nanoparticles in a cluster in the range of 0.04–0.2.

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Heating ability of elongated magnetic nanoparticles

10.3762/bxiv.2021.73.v1 ◽

2021 ◽

Author(s):

Elizaveta M Gubanova ◽

Nikolai A Usov ◽

Vladimir A Oleinikov

Keyword(s):

Magnetic Field ◽

Magnetite Nanoparticles ◽

Volume Fraction ◽

Low Frequency ◽

Hysteresis Loops ◽

Dipole Interaction ◽

Alternating Magnetic Field ◽

Particle Sizes ◽

Order Of Magnitude ◽

Elongated Nanoparticles

Low-frequency hysteresis loops and specific absorption rate (SAR) of various assemblies of elongated spheroidal magnetite nanoparticles have been calculated for a range of particle semiaxis ratios a/b = 1.0 – 3.0. The SAR of a dilute randomly oriented assembly of magnetite nanoparticles in an alternating magnetic field of moderate frequency, f = 300 kHz, and amplitude H0 = 100 - 200 Oe is shown to decrease significantly with an increase in the aspect ratio of nanoparticles. In addition, there is a narrowing and shift of the intervals of optimal particle diameters towards smaller particle sizes. However, the orientation of a dilute assembly of elongated nanoparticles in a magnetic field leads to an almost twofold increase in SAR at the same frequency and amplitude of the alternating magnetic field, the range of optimal particle diameters remaining unchanged. The effect of the magneto-dipole interaction on the SAR of an assembly of oriented clusters of elongated magnetite nanoparticles has also been investigated depending on the volume fraction of nanoparticles in a cluster. It has been found that the SAR of the assembly of oriented clusters decreases by approximately an order of magnitude with an increase in the volume fraction of nanoparticles in a cluster in the range 0.04 - 0.2.

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Heating ability of magnetic nanoparticles with cubic and combined anisotropy

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.10.29 ◽

2019 ◽

Vol 10 ◽

pp. 305-314 ◽

Cited By ~ 13

Author(s):

Nikolai A Usov ◽

Mikhail S Nesmeyanov ◽

Elizaveta M Gubanova ◽

Natalia B Epshtein

Keyword(s):

Magnetite Nanoparticles ◽

Magnetic Nanoparticle ◽

Specific Absorption Rate ◽

Magnetic Moments ◽

Low Frequency ◽

Hysteresis Loops ◽

Dipole Interaction ◽

Thermal Fluctuations ◽

Fractal Clusters ◽

Cubic Anisotropy

The low frequency hysteresis loops and specific absorption rate (SAR) of assemblies of magnetite nanoparticles with cubic anisotropy are calculated in the diameter range of D = 20–60 nm taking into account both thermal fluctuations of the particle magnetic moments and strong magneto–dipole interaction in assemblies of fractal-like clusters of nanoparticles. Similar calculations are also performed for assemblies of slightly elongated magnetite nanoparticles having combined magnetic anisotropy. A substantial dependence of the SAR on the nanoparticle diameter is obtained for all cases investigated. Due to the influence of the magneto–dipole interaction, the SAR of fractal clusters of nanoparticles decreases considerably in comparison with that for weakly interacting nanoparticles. However, the ability of magnetic nanoparticle assemblies to generate heat can be improved if the nanoparticles are covered by nonmagnetic shells of appreciable thickness.

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Heat generation by an alternating magnetic field of low frequency in a ferrofluid: the dependence of energy dissipation on temperature

Magnetohydrodynamics ◽

10.22364/mhd.44.1.4 ◽

2008 ◽

Vol 44 (1) ◽

pp. 27-32 ◽

Cited By ~ 1

Author(s):

M.M. Maiorov ◽

E. Blums ◽

G. Kroņkalns

Keyword(s):

Magnetic Field ◽

Energy Dissipation ◽

Heat Generation ◽

Low Frequency ◽

Alternating Magnetic Field

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Extremely low frequency alternating magnetic field–triggered and MRI–traced drug delivery by optimized magnetic zeolitic imidazolate framework-90 nanoparticles

Nanoscale ◽

10.1039/c5nr08086j ◽

2016 ◽

Vol 8 (6) ◽

pp. 3259-3263 ◽

Cited By ~ 31

Author(s):

Jie Fang ◽

Yong Yang ◽

Wen Xiao ◽

Bingwen Zheng ◽

Yun-Bo Lv ◽

...

Keyword(s):

Magnetic Field ◽

Drug Delivery ◽

Drug Release ◽

Low Frequency ◽

Alternating Magnetic Field ◽

Zeolitic Imidazolate Framework ◽

Extremely Low Frequency

An extremely low frequency alternating magnetic field of 20 Hz was proved to be able to remarkably accelerate the drug release from optimized ZIF-90 nanospheres with incorporated Fe3O4 nanoparticles acting as actuator.

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