The wavelength and concentration dependence of the magneto-dielectric anisotropy effect in magnetic fluids determined from magneto-optical measurements

Versatile transmission ellipsometry to study linear ferrofluid magneto-optics

“…A few exceptions are the papers by Llewellyn [14] and Yusuf et al [33]. In the former, the wavelengthdependent birefringence and dichroism of ferrofluids, consisting of (i) Fe 3 O 4 in diester and (ii) Co in toluene, are presented in the range of 300-700 nm.…”

Novel properties and applications in magnetic fluids

“…In almost all reported works, the C-M rotation of magnetic ¯uid ®lms was indirectly calculated from the measured transmittance and the maximum and the minimum transmitted intensity through the ®lms under a given magnetic ®eld [21,22,36,65]. The experimental details were illustrated in Ref.…”

“…It was observed that the birefringence is depressed at higher temperatures. A few years later, they reported the concentration and the wavelength dependent of the birefringence of magnetic ¯uid ®lms [22]. The experimental results showed that the birefringence was enhanced for a sample of a higher concentration and that an optimum birefringence occurred at a wavelength around 500 nm.…”

“…The experimental results showed that the birefringence was enhanced for a sample of a higher concentration and that an optimum birefringence occurred at a wavelength around 500 nm. These results were then explained in terms of the theory of dispersion of electromagnetic waves in the matter with the assumption that the density of charge carriers oscillating in a given direction is proportional to the number of particles orientated in that direction [22].…”

Agglomeration and chain formation in ferrofluids: Two-dimensional x-ray scattering

“…Theoretical investigations, treating ferrofluids as dipolar hard sphere liquids, [10][11][12][13][14] predict that a strong dipole-dipole interaction leads to the formation of chainlike or ringlike structures, in which the particle magnetic moments are aligned in a nose-to-tail manner. When an external magnetic field is applied, ferrofluids develop anisotropic properties, e.g., dielectric 15,16 or optical 17,18 anisotropy. It is evident that this must be due to a field-induced anisotropic microstructure, i.e., due to the presence of nonspherical units ͑particles or clusters͒ having an orientation parallel to the applied magnetic field.…”