Specific Absorption Rates and Magnetic Properties of Ferrofluids with Interaction Effects at Low Concentrations

Urtizberea, A. ; Natividad, E. (Universidad de Zaragoza) ; Arizaga, A. ; Castro, M. (Universidad de Zaragoza) ; Mediano Heredia, A. (Universidad de Zaragoza)

Resumen: 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.

Idioma: Inglés

DOI: 10.1021/jp912076f

Año: 2010

Publicado en: Journal of physical chemistry. C. 114, 11 (2010), 4916-4922
ISSN: 1932-7447

Factor impacto JCR: 4.524 (2010)

Categ. JCR: CHEMISTRY, PHYSICAL rank: 27 / 125 = 0.216 (2010) - Q1 - T1
Categ. JCR: NANOSCIENCE & NANOTECHNOLOGY rank: 14 / 63 = 0.222 (2010) - Q1 - T1
Categ. JCR: MATERIALS SCIENCE, MULTIDISCIPLINARY rank: 22 / 221 = 0.1 (2010) - Q1 - T1

Financiación: info:eu-repo/grantAgreement/ES/MICINN/CSD2007-00010
Financiación: info:eu-repo/grantAgreement/ES/MICINN/MAT2007-61621

Tipo y forma: Artículo (PostPrint)

Área (Departamento): Área Tecnología Electrónica (Dpto. Ingeniería Electrón.Com.)
Área (Departamento): Área Cienc.Mater. Ingen.Metal. (Dpto. Ciencia Tecnol.Mater.Fl.)