A novel experimental approach for direct observation of magnetic field induced structuration in ferrofluid

Abstract This article proposes a novel approach to investigate the field-induced structuration in ferrofluids (FFs) at room temperature. The in-house experimental setup has been fabricated to perceive the influence of dipolar interaction and particle size of dispersed magnetic nanoparticles (MNPs) in FFs on the static magneto-optical (MO) properties under the influence of an external magnetic field. The diffraction fringes are observed in FF when a high-power laser passing from the diluted fluid system which appearing at a specific dilution and varies with the different sizes and volume fraction of MNPs. The change in shape and size of the diffraction fringes is observed with the variation of both, size of dispersed MNPs and the dilation of the FFs which is used to calculate the refractive index coefficient. The number of diffraction rings increases with an increase in the size of dispersed MNPs and its diameter decrease with an increase in particle volume fraction. The effect of thermal lens and nonlinear optical (NLO) behavior gives the validation of field-induced refractive index coefficient appearing in FFs commutated by the fringe diffraction method. Further, the variation of intensity of transmitted light has been corroborated with the forward scattering resulting from the Brownian motion of the nanoparticle. The experiment validates the chain formation in FFs, as MNPs are working as mesoscopic cylinders resulting in specified scattering patterns. This experimental approach can lead to a new pathway for the development of potential applications such as tunable optical filters, optical limiters, and various photonics fields based on the tunable MO properties of FFs.