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High frequency hysteresis losses on gamma-Fe_2O_3 and Fe_3O_4: susceptibility as a magnetic stamp for chain formation

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Morales Casero, Irene and Hernando Grande, Antonio and Presa Muñoz del Toro, Patricia Marcela de la and Costo Cámara, Rocío and Mille, Nicolas and Bezerra Da Silva, Gustavo and Carrey, Julian (2018) High frequency hysteresis losses on gamma-Fe_2O_3 and Fe_3O_4: susceptibility as a magnetic stamp for chain formation. Nanomaterials, 8 (12). ISSN 2079-4991

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Official URL: http://dx.doi.org/10.3390/nano8120970


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Abstract

In order to understand the properties involved in the heating performance of magnetic nanoparticles during hyperthermia treatments, a systematic study of different gamma-Fe_2O_3 and Fe_3O_4 nanoparticles has been done. High-frequency hysteresis loops at 50 kHz carried out on particles with sizes ranging from 6 to 350 nm show susceptibility chi increases from 9 to 40 for large particles and it is almost field independent for the smaller ones. This suggests that the applied field induces chain ordering in large particles but not in the smaller ones due to the competition between thermal and dipolar energy. The specific absorption rate (SAR) calculated from hysteresis losses at 60 mT and 50 kHz ranges from 30 to 360 W/g_Fe, depending on particle size, and the highest values correspond to particles ordered in chains. This enhanced heating efficiency is not a consequence of the intrinsic properties like saturation magnetization or anisotropy field but to the spatial arrangement of the particles.


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©2018 by the authors.
This research was funded by COST action RADIOMAG (TD1402), supported by COST (European Cooperation in Science and Technology), by the Spanish Ministry of Economy and Competitiveness (MAT2015-67557-C2-1-P), and by Nanomag European project (604448) seventh framework program.

Uncontrolled Keywords:Iron-oxide nanoparticles; Heating efficiency; Absorption rate; Hyperthermia; Size; Surface; Particles; Field; Fluid; Shape; Magnetic nanoparticles; Specific absorption rate; Iron oxide
Subjects:Sciences > Physics > Materials
Sciences > Physics > Solid state physics
ID Code:51131
Deposited On:13 Feb 2019 15:55
Last Modified:13 Feb 2019 16:03

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