Magnetic field induced assembling of nanoparticles in ferrofluidic liquid thin films based on Ni x Fe1−x Fe2O4

Abstract

Ultra fine precursors for ferrofluid synthesis, belonging to the series, Ni x Fe 1-x Fe 2 O 4 (where 'x' varies from '0' to '0⋅ ⋅6' in steps of 0⋅ ⋅1), were synthesized. Ferrofluids based on these fine particles were prepared with oleic acid as surfactant and kerosene as carrier. Ferrofluidic thin films were made on glass substrates and magnetic field induced laser transmission was studied. The pattern exhibited by the films under the influence of a magnetic field was observed with the help of a CCD camera. The analysis of results confirms the chain formation of particles in the presence of an applied magnetic field and their saturation at higher applied fields. Keywords. Ferrofluids; nickel ferrite; field induced assembling; ultra fine particles.

Magnetic field-induced cluster formation and variation of magneto-optical signals in zinc-substituted ferrofluids

“…Cluster formation dictates the scattered intensity from moderately high applied magnetic fields and the diffraction effects are dominated. The transmitted intensity remains steady after the saturation in cluster formation [29,30].…”

Light scattering from a magnetically tunable dense random medium with dissipation: ferrofluid

“…This can be seen from the following geometrical considerations based on the fact that in a magnetic field (∼ 100 G) the nanoparticles are known to re-arrange forming chains aligned parallel to the field [8][9][10][11]. Assuming that the overall number density of the ferrofluid remains unchanged, we have 1/n F F = 2a N P d 2 , where 2a N P is the nanoparticle spacing along the chains and d the interchain separation.…”

“…We now consider more explicitly how the applied magnetic field tunes the scattering properties of the ferrofluid. There is ample evidence that the nanoparticles (nanomagnets) rearrange to form spatially ordered structures, like linear chains directed along the magnetic field [8][9][10][11].…”

Ferrofluid thin films as optical gaussmeters proposed for field and magnetic moment sensing

“…The most important application of this is in the magneto-optical applications where we have to simultaneously measure the magnetic field with the optical signal outputs normally. A more detailed investigation of the results have been provided in earlier publications (Abraham et al 2004;Swapna Nair et al 2006). Composition 'x' well as magnetic field and laser output such that the ferrofluid film can be employed as a magnetic field and moment sensor.…”