The Effect of Surface Plasmonic Resonances and Enhancement of the Optical Response on Magneto-Plasmonic Fe3O4@Ag Spherical Core-Shell Nanoparticles
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Date
2024-06
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Addis Ababa University
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, electric polarizability, refractive index, absorbance, as well as the corresponding scattering and absorption cross-sections. Moreover, for a fixed size of NPs (of radius r2 = 30 nm) numerical analysis is carried out to see the effect of varying the metal fraction (_), the filling fraction (f), and the permittivity ("h) 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, absorbance, extinction cross-sections 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 couplings of the surface plasmon oscillations of silver with the semiconductor/dielectric at the inner
(Fe3O4/Ag) and outer (Ag/host) interfaces. Moreover, the two set of resonance peaks are found to be enhanced with an increase of _, f, or "h; keeping two of these parameters constant at a time. On the other hand for the case of absorption and extinction cross-sections, as _ increases, the absorption and scattering cross-sections are blueshifted in the first peak and red shifted in the second set of peaks. Similarly, as "h increases or as _ decreases, the sets of resonance peaks for extinction cross-section get enhanced. The results obtained might be utilized in a variety of applications that are designed to integrate plasmonic effects of noble metals with magnetic semiconductors in a core/shell nanostructure ranging from UV to Visible spectral regions.
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Effect of Surface, Plasmonic Resonances, Enhancement, Optical Response on Magneto-Plasmonic, Fe3O4@Ag Spherical Core-Shell Nanoparticles