The modulation of coupling in the relaxation behavior of light transmitted through binary ferrofluids

With an external magnetic field, a relaxation process is observed when the light transmit through binary ferrofluids composed of ferrimagnetic CoFe2O4 and paramagnetic p-NiFe2O4 nanoparticles similar to ferrofluids consisting only of CoFe2O4. Since only the ferrimagnetic nanoparticles are able to form field-induced chainlike structures for such binary ferrofluids by magnetic interaction between the particles, so the relaxation behavior of the transmitted light is caused mainly by the ferrimagnetic system. In the binary ferrofluids, the paramagnetic nanoparticles, regarded as magnetically polarized gas molecules, are restrained to occupy the space between the ferrimagnetic chains and distribute following the CoFe2O4 particle chains covering and diverging, producing a modulation effect on the relaxation behavior of the transmitted light. The modulation effect can be characterized by range and time parameters that describe the relationship of the relaxation behavior of the transmitted light to the properties of the binary ferrofluids and single CoFe2O4 ferrofluids.