The influence of the Néel rotation on the magnetic induced dichroism in magnetic fluids

Versatile transmission ellipsometry to study linear ferrofluid magneto-optics

“…Both experimental and theoretical work is focused on elucidating the origin of the magneto-optical properties of these suspensions and exploring their applicability as active optical devices [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. Initially, the theoretical description of the magneto-optical properties of ferrofluids was based on the alignment of slightly non-spherical particles with uniaxial magnetic anisotropy in an applied magnetic field [9].…”

Ferrofluids and bio-ferrofluids: looking back and stepping forward

“…The nonlinear fit of dichroism data from a ferrofluid with 2% volume magnetite nanoparticles dispersed in transformer oil, with the models for Brown 246 and Néel 259 rotation, proved the validity of the latter, leading to a realistic and closer to TEM value of the nanoparticle ellipticity. 276 Dynamic magneto-optic effects in the case of cobaltferrite and maghemite MF samples with anisotropy fields differing by an order of magnitude reveal essential differences in what concerns the magnetic field dependence of the charac-teristic relaxation time. 274 Magnetic field dependence of relaxation time is quite different for σ ≫ 1 compared to σ ≈ 1.…”

Field induced phase segregation in ferrofluids

“…This effect is well-known and forms the basis of the anisotropic optical properties of ferrofluids subjected to an external field. Since the first discovery of magnetic birefringence and dichroism in these liquids [18,19], substantial research efforts have been focused on elucidating the origin of the magneto-optical properties and exploring their possible application as active optical devices, such as shutters, switches, polarizers and phase-changing elements [20][21][22][23][24][25][26][27][28][29][30].…”