Reliable methods for studying the magnetization dynamics of metal ferrite nanoparticles (NP) are needed, as these particles are attractive candidates for biomedical applications such as in targeted drug delivery, imaging, and magnetic hyperthermia. We investigate magnetic response of various iron oxide NP in aqueous solution was investigated by performing Faraday Rotation (FR) experiments under pulsed fields (typically 0.6 Tesla and 100 to 150 ms in duration) and as a function of excitation frequency using the magneto-optic technique of AC Faraday rotation. Comparisons of the results yield interesting insights about the behavior of these particles in different field environments. Solutions of varying concentration were prepared from Fe3O4 (Magnetite) and Fe2O3 (Maghemite) NPs having an average diameter of 10 nm. The AC measurement technique is sensitive to changes in the solutions’ nanoparticle volume fractions as small as 2 x 10-6. On the other hand, strength of the pulsed field method lies in the fact that it can provide a live “snapshot” of the magnetization dynamics. This two-prong analysis of magnetization dynamics will complement future work which seeks to understand the effects of nanoparticle bonding with bio molecules and the resulting changes to the particles’ hydrodynamic radii and relaxation times.