Abstract
In this work, the optical properties of Fe3O4@Ag core/shell spherical nanostructures embedded in a dielectric host matrix are investigated theoretically. The theoretical analysis is carried out based on the electrostatic approximation and Maxwell-Garnet effective medium theory to obtain the effective electric permittivity and magnetic permeability, as well as the corresponding refractive index and absorbance. Moreover, for a fixed size of NPs (of radius r2=30nm) numerical analysis is carried out to see the effect of varying the metal fraction (the volume fraction of the metallic shell) (β), the filling fraction (the volume fraction of inclusions in the composite) (f), and the permittivity (εh) of the host matrix on the optical properties of the nanostructures. The results show that graphs of real and imaginary parts of polarizability, refractive index and absorbance as a function of wavelength possess two sets of resonance peaks in the UV and visible regions. These sets of peaks arise due to the strong coupling/interactions of the surface plasmon oscillations of silver with the semiconductor/dielectric at the inner (Fe3O4/Ag) and outer (Ag/host) interfaces and/or to near-field inter-particle interaction. Moreover, the two set of resonance peaks are found to be enhanced with an increase of β,f, or εh; keeping two of these parameters constant at a time. The results obtained can be used in applications that are designed to integrate plasmonic effects of noble metals with magnetic semiconductors in a core/shell nanostructure.
Published Version
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