133142 20240322124130.0 doi 10.1021/jp912076f sideral 67021 ART-2010-67021 eng Urtizberea, A. (orcid)0000-0002-8424-9780 Specific Absorption Rates and Magnetic Properties of Ferrofluids with Interaction Effects at Low Concentrations 2010 The specific absorption rate (SAR) of a maghemite-based ferrofluid, measured at 315 K, 3 kA/m, and 109 kHz, was found to double as the ferrofluid concentration was decreased by a factor of 4. The ferrofluid contained nonagglomerated, highly crystalline, and monodisperse nanoparticles with an average size of 11.6 nm and an initial concentration of 8.14 mg/mL. The magnetic characterization of three different concentrations of this ferrofluid revealed several effects typical of the presence of magnetic interactions, such as the decrease of initial susceptibility values (liquid ferrofluid) and Néel relaxation times, τN (frozen ferrofluid), with increasing concentration. The accurate SAR determination in adiabatic conditions allowed estimating the τN values of the liquid ferrofluid, which displayed the same trend against concentration as those obtained in the frozen state. Such a trend allowed explaining qualitatively the degradation of the heating performance of the ferrofluid upon increasing concentration. Eventually, correlation between τN values in both states was discussed in terms of several theoretical models described in the literature and developed to explain the properties of an assembly of nanoparticles with dipolar interactions. Access copy available to the general public Unrestricted info:eu-repo/grantAgreement/ES/MICINN/CSD2007-00010 info:eu-repo/grantAgreement/ES/MICINN/MAT2007-61621 info:eu-repo/semantics/openAccess All rights reserved http://www.europeana.eu/rights/rr-f/ 4.524 2010 CHEMISTRY, PHYSICAL 27 / 125 = 0.216 2010 Q1 T1 NANOSCIENCE & NANOTECHNOLOGY 14 / 63 = 0.222 2010 Q1 T1 MATERIALS SCIENCE, MULTIDISCIPLINARY 22 / 221 = 0.1 2010 Q1 T1 info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion Natividad, E. Universidad de Zaragoza (orcid)0000-0003-2553-0633 Arizaga, A. Castro, M. Universidad de Zaragoza (orcid)0000-0002-9687-4903 Mediano Heredia, A. Universidad de Zaragoza (orcid)0000-0002-4099-9918 5008 785 Universidad de Zaragoza Dpto. Ingeniería Electrón.Com. Área Tecnología Electrónica 5001 065 Universidad de Zaragoza Dpto. Ciencia Tecnol.Mater.Fl. Área Cienc.Mater. Ingen.Metal. 114, 11 (2010), 4916-4922 J. phys. chem., C Journal of physical chemistry. C. 1932-7447 592792 http://zaguan.unizar.es/record/133142/files/texto_completo.pdf Postprint 1362133 http://zaguan.unizar.es/record/133142/files/texto_completo.jpg?subformat=icon icon Postprint oai:zaguan.unizar.es:133142 articulos driver 2024-03-22-09:47:50 ARTICLE