Work

Optimization of Magnetoplasmonic Behavior in Ag/Fe Bilayer Nanostructures Towards Refractometric Sensing

Year: 2025

Type: article

Abstract: Magneto-optic surface plasmon resonances (MOSPR) rely on the interaction of magnetic fields with surface plasmon polaritons (SPP) to both modulate plasmonic bands with magnetic fields and enhance magneto-optical activity.A comprehensive study of the magnetoplasmonic properties of Ag/Fe planar bilayers was performed by first simulating reflectance spectra using Berreman’s matrix formalism, from which an optimized structure composed of 15nm of Ag and 12.5nm of Fe was obtained. This selected structure was fabricated by RF magnetron sputtering and characterized for refractive index (RI) sensitivity in a Kretschmann setup. An MOSPR reflectance sensitivity to RI reached 4946 RIU-1, returning an effective enhancement of refractometric sensitivity after magneto-optical modulation.A new, optimized, and cobalt-free magnetoplasmonic Ag/Fe bilayer structure was studied, fabricated, and characterized for enhanced sensitivity, being reported for the first time, to the best of our knowledge. This configuration exhibits potential for enhancing refractometric sensitivity via magneto-optical modulation, thus casting the way to a simpler, more accessible, and safe type of RI sensor, with potential applications in chemical sensors and biosensors.

Source: Sensors

DOI: 10.3390/s25051419

Authors: João Pedro Carvalho, Bernardo Dias, Luís Coelho, José Almeida