Magneto-optical effects of MgFe<inf>2</inf>O<inf>4</inf> nanoparticles in solutions and thin films of polystyrene using digital Mach-Zehnder interferometer: An optical based sensor for energy storage controller

Abstract

In this work, the effects of magnetic fields on the refractive index profiles and induced birefringence of polystyrene/MgFe2O4 nanoparticles (15 nm) solutions and thin films were investigated. Both the refractive index and the induced birefringence profiles of the solutions and thin films were investigated as a function of the applied magnetic field strength using the digital two-beam Mach-Zehnder interferometric method. Image processing algorithm, based on the fast Fourier transform (FFT) analysis, was applied to extract the optical phase differences of the recorded micro-interferograms for all samples under investigation. Then the refractive index and birefringence profiles are calculated. A good correlation between the applied magnetic field and the change of refractive index (Δn) was obtained (R2 ~ 0.94). This could be useful for electric energy storage sensors based on the magneto-optical properties of polystyrene/MgFe2O4 solutions and thin films.