CONCENTRATION AND TEMPERATURE EFFECT IN THE MICROSTRUCTURE OF FERROFLUIDS

摘要

The spatial correlations in magnetite-based ferrofluids (FF) with pentanol carrier have been investigated by small-angle neutron scattering as dependent on the concentration of the magnetic phase (C = 0.6-20% vol.) and temperature (20-85℃). Some peculiarities in the structure of the FF were detected, such as an anomalous increase of short range order by heating of low concentrated FF (C～0.6-4.0% vol.), the formation of short range order at ambient temperature which weakens at growing concentrations C=7-14% vol., the existence of the stable structure at the highest concentration C～20% vol. when particles shells interpenetrate. Neutron scattering data are discussed regarding to particles intrinsic magnetisation enhancement induced by ordering.