The Effect of Magnetic Field on the Structure Formation in an Oil-Based Magnetic Fluid with Multicore Iron Oxide Nanoparticles

This study focuses on synthesis and characterization of fluid consisting of lecithin coated multi-core magnetic magnetite particles. The chemical structure of lecithin is responsible for the formation of multi-core structure. The strong enhancement in an average magnetic moment of cluster compares to single core structure confirms the formation of multi-core structure with coherence orientation of magnetic moments. This is confirmed by thermo-gravimetric analysis. This enables confident conclusions about the effect of magnetic field induced structure on the flow behaviour. The variation of yield stress with dilution at a given magnetic field is explained using the microscopic theory proposed by Zubarev et al. The results indicate that on dilution, the multicore concentration decreases rather than number concentration of single core in a system.