Tunable Curie temperature of Mn0.6Zn0.4Fe2O4 nanoparticles

Synthesis of stable temperature sensitive magnetic fluids that can be used in heat exchange devices having desired magnetic properties and tunable Curie temperature is quite challenging as their performance parameters are strongly correlated with preparation conditions of magnetic nanoparticles. In this article, we report size dependence of Curie temperature and saturation magnetization of Mn0.6Zn0.4Fe2O4 (MZ4) nanoparticles synthesized by co-precipitation method by controlling the pH, reaction temperature and reaction time. As-synthesized MZ4 nanoparticles have tunable Curie temperature that ranges between 392 K and 665 K. These magnetic nanoparticles are well suited for cooling applications in energy conversion electronic devices as their Curie temperatures are close to the working temperature of these devices. The observed tunability of Curie temperature and magnetization of MZ4 nanoparticles are analysed in terms of the corresponding changes in the magnetic particle size and distribution of Mn ions between tetrahedral (A-site) and octahedral (B-site) in an inverse spinel structure.