The static magnetic birefringence (SMB) of nickel-ferrite ionic magnetic fluid was investigated within the oscillating dipole-interaction anisotropy concept proposed by Xu and Ridler [J. Appl. Phys. 82, 326 (1997)]. The model was extended to include the magnetic texture of particle agglomerates and the field dependence of the magnetic permeability. The SMB data of samples subjected or not to a magnetic aging process and presenting particle concentration in the range of 2×1016 to 8×1016 particle/cm3 were successfully described. The particle size distribution obtained from the fit of the SMB data was discussed in comparison with the data obtained from transmission electron microscopy.
Atomic force microscopy (AFM), transmission electron microscopy (TEM), and static magnetic birefringence (SMB) were used to unfold the particle size polydispersity profile of a magnetite-based magnetic fluid sample. The data obtained from different techniques were curve fitted using the lognormal distribution function, from which the mean particle diameter (Dm) and the standard deviation (σ) were obtained. In comparison to the TEM data, the AFM data show a reduction of Dm (about 20%) and an increase of σ (about 15%). In contrast, close agreement between the TEM and SMB data was found.
The magneto-optical properties of a highly stable ionic magnetic fluid sample containing CdFe2O4 nanoparticles were investigated using static magnetic birefringence, zero-field optical transmissivity, and transmission electron microscopy. From our measurements we found that the transmittivity and the birefringence of the CdFe2O4-based sample is several times greater than a typical magnetic fluid sample (γ-Fe2O3 based), giving this magnetic material great potential for magneto-optics applications. We also found that the birefringence can be increased by several orders of magnitude, allowing full manipulation of the observed negative differential transmitted optical intensity feature.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.