Abstract
Magneto-plasmonic core/shell nanoparticles are used in many modern devices due to their combined magnetic and plasmonic properties. In this study, scattering light by Ni/Au core/shell nanoparticle with spherical shape was studied based on the Mie theory. The effects of Au shell layer thickness, Ni core diameter, and surrounding medium on the scattering efficiencies have been reported. The surface plasmon resonances of Ni/Au are red-shifted over a broad spectral range from the visible to infrared by simply increasing core diameter Ni, or shell thickness of Au, which is the result of reducing the restoring force. This shift is along with an increase in the scattering intensity. The higher-order plasmon modes are evident of large nanoparticles, which cause the spectra to be more complicated compared to pure Au and Ni nanoparticles. Also, the width of the resonance peak gradually become broader as the nanoparticle size increases. Moreover, the scattering peak experiences a red-shift with the increase in the surrounding refractive index due to the strong polarization of the surrounding medium. The fundamental resonance peak is rapidly shifting to a higher wavelength than other higher order peaks, with an estimated sensitivity of 1290.36 nm/RIU. This result suggests that the Ni/Au has a higher sensitivity to the surrounding refractive index than previously reported data. These reported results might motivate the experimentalists to synthesize Ni/Au core/shell to be used in many applications such as photothermal, sensors, photocatalysis, optical imaging, solar cells, and cancer therapy.