scholarly journals Larmor Precession and Debye Relaxation of Single-Domain Magnetic Nanoparticles

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Zs. Jánosfalvi ◽  
J. Hakl ◽  
P. F. de Châtel
Keyword(s):  
Magnetic Nanoparticles ◽  
Magnetic Fields ◽  
Analytical Solutions ◽  
Power Dissipation ◽  
Single Domain ◽  
Larmor Precession ◽  
Qualitative Comparison ◽  
Debye Relaxation ◽  
Linearly Polarized ◽  
Exponential Relaxation

The numerous phenomenological equations used in the study of the behaviour of single-domain magnetic nanoparticles are described and some issues clarified by means of qualitative comparison. To enable a quantitativeapplicationof the model based on the Debye (exponential) relaxation and the torque driving the Larmor precession, we present analytical solutions for the steady states in presence of circularly and linearly polarized AC magnetic fields. Using the exact analytical solutions, we can confirm the insight that underlies Rosensweig’s introduction of the “chord” susceptibility for an approximate calculation of the losses. As an important consequence, it can also explain experiments, where power dissipation for both fields was found to be identical in “root mean square” sense. We also find that this approximation provides satisfactory numerical accuracy only up to magnetic fields for which the argument of the Langevin function reaches the value 2.8.

Precessional dynamics of single-domain magnetic nanoparticles driven by small ac magnetic fields

2006 ◽  
Vol 39 (22) ◽  
pp. 4746-4752 ◽  
Author(s):  
Haiwen Xi ◽  
Kai-Zhong Gao ◽  
Yiming Shi ◽  
Song Xue
Keyword(s):  
Magnetic Nanoparticles ◽  
Magnetic Fields ◽  
Single Domain

Thermal Conductivity Enhancement of Room Temperature Ionic Liquids (RTILs) With Various Magnetic Nanoparticles

2012 ◽  
Author(s):  
N. Y. Jagath B. Nikapitiya ◽  
Hyejin Moon
Keyword(s):  
Thermal Conductivity ◽  
Ionic Liquids ◽  
Magnetic Nanoparticles ◽  
Magnetic Fields ◽  
Room Temperature ◽  
Particle Concentration ◽  
Thermal Conductivity Enhancement ◽  
Room Temperature Ionic Liquids ◽  
Conductivity Enhancement ◽  
Magnetic Nanofluids

This paper reports an experimental study of thermal conductivity of room temperature ionic liquids (RTILs) based magnetic nanofluids. Various magnetic nanoparticles of metal oxides with high thermal conductivity, such as CuO, Al2O3, Fe3O4 and Carbon Nano Tubes (CNTs), were used to prepare magnetic nanofluids, while RTIL, trihexyl (tetradecyl) posphonium dicyanamide was used as the base fluid. Two major parameters that affect to the thermal conductivity enhancement of fluids were investigated. The effect of particle concentration and external magnetic fields were tested. It was observed that the magnetic nanofluids thermal conductivities increase with increment of particle concentration and external magnetic field parallel to the temperature gradient. Besides, it was observed that under higher magnetic fields, thermal conductivity enhancement tends to approach a saturation state. Surfactant was used to disperse magnetic nanoparticles within the RTILs. The transient hot wire method was used for this investigation.

scholarly journals Localized Dielectric Loss Heating in Dielectrophoresis Devices

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Tae Joon Kwak ◽  
Imtiaz Hossen ◽  
Rashid Bashir ◽  
Woo-Jin Chang ◽  
Chung Hoon Lee
Keyword(s):  
Numerical Analysis ◽  
Dielectric Loss ◽  
Power Dissipation ◽  
Temperature Sensor ◽  
Thermal Mass ◽  
Experiment Data ◽  
Debye Relaxation ◽  
Heating Mechanism ◽  
Biological Entities ◽  
Good Agreement

AbstractTemperature increases during dielectrophoresis (DEP) can affect the response of biological entities, and ignoring the effect can result in misleading analysis. The heating mechanism of a DEP device is typically considered to be the result of Joule heating and is overlooked without an appropriate analysis. Our experiment and analysis indicate that the heating mechanism is due to the dielectric loss (Debye relaxation). A temperature increase between interdigitated electrodes (IDEs) has been measured with an integrated micro temperature sensor between IDEs to be as high as 70 °C at 1.5 MHz with a 30 Vpp applied voltage to our ultra-low thermal mass DEP device. Analytical and numerical analysis of the power dissipation due to the dielectric loss are in good agreement with the experiment data.

Triggering Passive Molecular Transport into Cells with a Combination of Inhomogeneous Magnetic Fields and Magnetic Nanoparticles

2020 ◽  
Vol 3 (3) ◽  
pp. 2414-2420 ◽  
Author(s):  
Wasundara Hulangamuwa ◽  
Basanta Acharya ◽  
Viktor Chikan ◽  
Ryan J. Rafferty
Keyword(s):  
Magnetic Nanoparticles ◽  
Magnetic Fields ◽  
Molecular Transport

scholarly journals Quantification of magnetic nanoparticles with low frequency magnetic fields: compensating for relaxation effects

2013 ◽  
Vol 24 (32) ◽  
pp. 325502 ◽  
Author(s):  
John B Weaver ◽  
Xiaojuan Zhang ◽  
Esra Kuehlert ◽  
Seiko Toraya-Brown ◽  
Daniel B Reeves ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Magnetic Fields ◽  
Low Frequency ◽  
Relaxation Effects

Relaxation of biofunctionalized magnetic nanoparticles in ultra-low magnetic fields

2013 ◽  
Vol 113 (4) ◽  
pp. 043911 ◽  
Author(s):  
H. C. Yang ◽  
L. L. Chiu ◽  
S. H. Liao ◽  
H. H. Chen ◽  
H. E. Horng ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Magnetic Fields
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