SIZING AND EDDY CURRENTS IN MAGNETIC CORE NANOPARTICLES: AN OPTICAL EXTINCTION APPROACH

LUIS JOAQUÍN MENDOZA HERRERA; IGNACIO J. BRUVERA; LUCÍA B. SCAFFARDI ; DANIEL CARLOS SCHINCA

PHYSICAL CHEMISTRY CHEMICAL PHYSICS

ROYAL SOC CHEMISTRY

Lugar: CAMBRIDGE; Año: 2017 vol. 19 p. 3076 - 3083

1463-9076

Optical extinction, is a handy and ubiquitous technique that allows to study colloidal nanoparticles in their native state. The typical analysis of the extinction spectrum can be extended in order to obtain structural information of the sample such as size distribution of the cores and thickness of the coating layers. In this work the extinction spectra of Fe3O4, Fe3O4@Au and Fe3O4@SiO2@Ausingle and multilayer nanoparticles are obtained by solving full Mie theory with a frequency dependent susceptibility derived from Gilbert equation and considering the effect of Eddy currents.The results are compared with non magnetic Mie theory, magnetic dipolar approximation and magnetic Mie theory without Eddy currents. The particle size-wavelength ranges of validity of these different approaches are explored and novel results are obtained for Eddy current effects in optical extinction. These results are used to obtain particles size and shell thickness informationfrom experimental extinction spectra of Fe3O4 and Fe3O4@Au nanoparticles with good agreement with TEM results, and to predict the plasmon peak parameters for Fe3O4@SiO2@Au three layer nanoparticles.