LAUSR

Abstract Although significant advances have been made by magnetite nanoparticles for the applications in magnetic hyperthermia, the optimization and related mechanism of heating efficiency is nevertheless a challenge. Fe3O4 nanoparticles are synthesized by solvothermal method at the different annealing temperature. The annealing regulated the activation energy in the reaction process and plays a major role in controlling the size and cation distribution in the spinel ferrite. In this work, we have carried out a comprehensive study on the impact of cation distribution towards tuning the structural and magnetic parameters and finally optimizing the heating efficiency of the nanoparticles for magnetic hyperthermia application. Characteristics structural parameters have been examined from X-ray diffraction spectra by employing standard Rietveld refinement techniques. Crystallite sizes as calculated from Uniform Stress Deformation Model are found to decrease with heat treatment as supported by the HRTEM study. Cation migration is confirmed from the XRD peak intensity and FTIR study. The saturation magnetization (MS) and magnetic anisotropy (Keff) extracted from the classical Langevin fitting of the M−H data are found to increase with the accelerating annealing temperature. This increase is ascribed to the dominance of cationic re-arrangement in the variation of magnetic parameters. The perceived specific absorption rate (SAR) for annealed nanoparticles are significantly higher than the un-annealed one. SAR escalates with intensifying annealing temperature. It can be established that the particle size and magnetic anisotropy plays a key role in enhancing the heating efficiency of the Fe3O4 nanoparticles.