Spectral analysis of external magnetic field influence on magnetic oxide nano-particles in ferrofluid

Abstract

Light transmitting measurements of white light and laser beam propagating through FeFe2O4, CoFe2O4 and MgFe2O4 nanoparticles coated with starch, citric and oleic acid, under the influence of an external magnetic field in the range of 30-400 mT, were presented. The unexpected and unusually large changes of transmitted light occurred. This can be explained by the model based on ordering of magnetic moments of nano-particles along the lines of magnetic field into magnetic chains and organization of magnetic chains into spatial structure - a quasi-lattice. Under the influence of external magnetic field, a precipitation of all studied samples was obtained. To the best of our knowledge, the field-induced precipitation effect of ferrites in ferrofluid was not analysed so far and its significance and influence on the further laser treatment of patients previously exposed to ferrite-based MRI agents is not well recognized. This should be of great importance, since neglecting of the precipitation effect would lead to inappropriate response when patients are exposed to diagnostic and/or therapy procedures.