Interaction of superparamagnetic and non-superparamagnetic particles in magnetic fluid

Abstract

Magnetic fluids are known to contain superparamagnetic and non-superparamagnetic particles. In this paper, an attempt has been made to show the interaction between superparamagnetic and non-superparamagnetic particles experimentally by measuring the initial susceptibility, over a wide temperature range, of manganese-zinc ferrite and cobalt ferrite magnetic fluids both separate and as mixtures. Likewise experiments were done with manganese-zinc ferrite and magnetite magnetic fluids. The results showed that when the percentage of non-superparamagnetic particles is high, the interaction is high when the particle rotations are restricted. The interaction was less for the system where the non-superparamagnetic particle fraction is small, as in the case of manganese-zinc ferrite and magnetite mixture. The above was true for both zero field cooled and field cooled cases.