Publication: Magnetic Nanoparticles for Power Absorption: optimizing size, shape and magnetic properties.
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Publication Date
2009-10
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Elsevier
Abstract
We present a Study on the magnetic properties of naked and silica-coated Fe₃O₄nanoparticles with sizes between 5 and 110 nm. Their efficiency as heating agents was assessed through specific power absorption (SPA) measurements as a function of particle size and shape. The results show a strong dependence of the SPA with the particle size, with a maximum around 30 nm, as expected for a Neel relaxation mechanism in single-domain particles. The SiO₂shell thickness was found to play an important role in the SPA mechanism by hindering the heat Outflow, thus decreasing the heating efficiency. It is concluded that a compromise between good heating efficiency and surface functionality for biomedical purposes can be attained by making the SiO₂functional coating as thin as possible.
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©Elsevier.
The authors acknowledge the financial support from Diputación General de Aragón, Comunidad de Madrid (S-0505/MAT/0194), and Ministerio de Ciencia e Innovación (MAT2005-03179 and MAT2008-01489). GFG and PP acknowledge support from the Spanish MEC through the Ramon y Cajal program.