Highest coercivity and considerable saturation magnetization of CoFe₂O₄ nanoparticles with tunable band gap prepared by thermal decomposition approach

The report states that well-dispersed CoFe₂O₄ nanoparticles (NPs) with controllable morphology were prepared using an economical and facile one-pot thermal decomposition approach. Cobalt (II) acetylacetonate and Iron (III) acetylacetonate were employed as precursors instead of expensive and toxic pentacarbonyl. The transmission electron microscopy and powder X-ray diffraction investigation show that CoFe₂O₄ NPs possess cubic morphology, homogeneous size distribution and pure phase structure. Optical band gap was tuned from 1.147 to 0.92 eV and saturation magnetization (M _s) increased from 53.91 to 84.01 emu/g for the as-prepared and annealed (700 °C) NPs. The coercivity (H _c) enhanced from 1137 to 2109 Oe at room temperature, which is the highest value reported to date for CoFe₂O₄ NPs synthesized by thermal decomposition. All CoFe₂O₄ (as-prepared and annealed) NPs showed excellent ferromagnetism behaviour at room temperature. Raman studies of CoFe₂O₄ NPs confirm the redistribution of Co²⁺ from octahedral to tetrahedral site. The work demonstrates the great potential of CoFe₂O₄ NPs as a promising alternative for data storage device applications as well as for opto-magnetic devices.