scholarly journals Effect of direct-current magnetic field on the specific absorption rate of metamagnetic CoMnSi: A potential approach to switchable hyperthermia therapy

AIP Advances ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 015128
Author(s):  
K. C. Ugochukwu ◽  
M. M. Sadiq ◽  
E. S. Biegel ◽  
L. Meagher ◽  
M. R. Hill ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Direct Current ◽  
Absorption Rate ◽  
Specific Absorption Rate ◽  
Specific Absorption ◽  
Potential Approach ◽  
Hyperthermia Therapy ◽  
Current Magnetic Field

scholarly journals Dynamics of superparamagnetic nanoparticle in viscous liquid in rotating magnetic field

2019 ◽  
Author(s):  
Nikolai A Usov ◽  
Ruslan A Rytov ◽  
Vasiliy A Bautin
Keyword(s):  
Magnetic Field ◽  
Viscous Liquid ◽  
Absorption Rate ◽  
Specific Absorption Rate ◽  
Stochastic Equation ◽  
Magnetization Vector ◽  
Superparamagnetic Nanoparticles ◽  
Rotating Magnetic Field ◽  
Field Frequency ◽  
Specific Absorption

The dynamics of magnetic nanoparticle in a viscous liquid in rotating magnetic field has been studied by means of numerical simulation and analytical calculations. In the magneto- dynamics approximation three different modes of motion of the unit magnetization vector and particle director are distinguished depending on the rotating magnetic field frequency and amplitude. The specific absorption rate of a dilute assembly of superparamagnetic nanoparticles in rotating magnetic field is calculated by solving the Landau – Lifshitz stochastic equation for unit magnetization vector and stochastic equation for particle director. At elevated frequencies an optimal range of particle diameters is found where the specific absorption rate of an assembly in rotating magnetic field has a maximum. It is shown that for magnetic hyperthermia in rotating magnetic field it is preferable to use rotating magnetic fields of moderate amplitude, H 0 = 100 Oe, in the frequency range 400-600 kHz.

scholarly journals Quantitative Analysis of the Specific Absorption Rate Dependence on the Magnetic Field Strength in ZnxFe3−xO4 Nanoparticles

2020 ◽  
Vol 21 (20) ◽  
pp. 7775
Author(s):  
Mohamed Alae Ait Kerroum ◽  
Cristian Iacovita ◽  
Walid Baaziz ◽  
Dris Ihiawakrim ◽  
Guillaume Rogez ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Relaxation Time ◽  
Absorption Rate ◽  
Specific Absorption Rate ◽  
Large Diameter ◽  
Precipitation Method ◽  
Magnetization Relaxation ◽  
Specific Absorption ◽  
The Magnetic Field ◽  
Néel Relaxation

Superparamagnetic ZnxFe3−xO4 magnetic nanoparticles (0 ≤ x < 0.5) with spherical shapes of 16 nm average diameter and different zinc doping level have been successfully synthesized by co-precipitation method. The homogeneous zinc substitution of iron cations into the magnetite crystalline structure has led to an increase in the saturation magnetization of nanoparticles up to 120 Am2/kg for x ~ 0.3. The specific absorption rate (SAR) values increased considerably when x is varied between 0 and 0.3 and then decreased for x ~ 0.5. The SAR values are reduced upon the immobilization of the nanoparticles in a solid matrix being significantly increased by a pre-alignment step in a uniform static magnetic field before immobilization. The SAR values displayed a quadratic dependence on the alternating magnetic field amplitude (H) up to 35 kA/m. Above this value, a clear saturation effect of SAR was observed that was successfully described qualitatively and quantitatively by considering the non-linear field’s effects and the magnetic field dependence of both Brown and Neel relaxation times. The Neel relaxation time depends more steeply on H as compared with the Brown relaxation time, and the magnetization relaxation might be dominated by the Neel mechanism, even for nanoparticles with large diameter.

scholarly journals Dynamics of superparamagnetic nanoparticles in viscous liquids in rotating magnetic fields

2019 ◽  
Vol 10 ◽  
pp. 2294-2303
Author(s):  
Nikolai A Usov ◽  
Ruslan A Rytov ◽  
Vasiliy A Bautin
Keyword(s):  
Magnetic Field ◽  
Absorption Rate ◽  
Specific Absorption Rate ◽  
Stochastic Equation ◽  
Magnetization Vector ◽  
Optimal Choice ◽  
Superparamagnetic Nanoparticles ◽  
Rotating Magnetic Field ◽  
Rotating Magnetic Fields ◽  
Specific Absorption

The dynamics of magnetic nanoparticles in a viscous liquid in a rotating magnetic field has been studied by means of numerical simulations and analytical calculations. In the magneto-dynamics approximation three different modes of motion of the unit magnetization vector and particle director are distinguished depending on frequency and amplitude of the rotating magnetic field. The specific absorption rate of a dilute assembly of superparamagnetic nanoparticles in rotating magnetic field is calculated by solving the Landau–Lifshitz stochastic equation for the unit magnetization vector and the stochastic equation for the particle director. At elevated frequencies an optimal range of particle diameters is found where the specific absorption rate of an assembly in a rotating magnetic field has a maximum. It is shown that with an optimal choice of the particle sizes sufficiently large SAR values of the order of 400–500 W/g can be obtained in a rotating magnetic field with a frequency f = 400 kHz and a moderate magnetic field amplitude H 0 = 100 Oe.

scholarly journals Magnetic Nanoparticles with High Specific Absorption Rate at Low Alternating Magnetic Field

Nano LIFE ◽  
2015 ◽  
Vol 05 (02) ◽  
pp. 1550002 ◽  
Author(s):  
K. Kekalo ◽  
I. Baker ◽  
R. Meyers ◽  
J. Shyong
Keyword(s):  
Magnetic Field ◽  
Magnetic Nanoparticles ◽  
Magnetic Nanoparticle ◽  
Absorption Rate ◽  
Specific Absorption Rate ◽  
Alternating Magnetic Field ◽  
Hyperthermia Treatment ◽  
Specific Absorption ◽  
New Type ◽  
Carboxymethyl Dextran

This paper describes the synthesis and properties of a new type of magnetic nanoparticle (MNP) for use in the hyperthermia treatment of tumors. These particles consist of 2–4 nm crystals of gamma- Fe 2 O 3 gathered in 20–40 nm aggregates with a coating of carboxymethyl-dextran, producing a zetasize of 110–120 nm. Despite their very low saturation magnetization (1.5–6.5 emu/g), the specific absorption rate (SAR) of the nanoparticles is 22–200 W/g at applied alternating magnetic field (AMF) with strengths of 100–500 Oe at a frequency of 160 kHz.

scholarly journals Specific absorption rate dependence on temperature in magnetic field hyperthermia measured by dynamic hysteresis losses (ac magnetometry)

2014 ◽  
Vol 26 (1) ◽  
pp. 015704 ◽  
Author(s):  
Eneko Garaio ◽  
Olivier Sandre ◽  
Juan-Mari Collantes ◽  
Jose Angel Garcia ◽  
Stéphane Mornet ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Absorption Rate ◽  
Specific Absorption Rate ◽  
Rate Dependence ◽  
Specific Absorption ◽  
Hysteresis Losses ◽  
Dynamic Hysteresis
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