Cobalt ferrite ( ) is an engineering material which is used for applications such as magnetic cores, magnetic switches, hyperthermia based tumor treatment, and as contrast agents for magnetic resonance imaging. Utility of ferrites nanoparticles hinges on its size, dispersibility in solutions, and synthetic control over its coercivity. In this work, we establish correlations between room temperature co-precipitation conditions, and these crucial materials parameters. Furthermore, post-synthesis

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... nnealing conditions are correlated with morphology, changes in crystal structure and magnetic properties. We disclose the synthesis and process conditions helpful in obtaining easily sinterable nanoparticles with coercive magnetic flux density ( ) in the range -kA/m and in the range -A m Kg . At a grain size of nm (corresponding to 1073 K sintering temperature), multi-domain behavior sets in, which is indicated by a decrease in . In addition, we observe an increase in lattice constant with respect to grain size, which is the inverse of what is expected of in ferrites. Our results suggest that oxygen deficiency plays a crucial role in explaining this inverse trend. We expect the method disclosed here to be a viable and scalable alternative to thermal decomposition based synthesis. The magnetic trends reported will aid in the optimization of functional nanoparticles. Index Terms-Cobalt compounds, ferrimagnetic materials, ferrites, magnetic materials. 0018-9464 © 2013 IEEE