LAUSR

High-performance cobalt ferrite nanoparticles (CoFe2O4 NPs) with controlled morphology were obtained by an economical and simple thermal decomposition technique. Cube-shaped CoFe2O4 NPs with different particle dimensions were achieved by precisely controlling the reaction refluxing time. The size-dependent magnetic properties were investigated and reported. The coercivity (Hc) of CoFe2O4 NPs increased with particle size upto single domain limit. Higher coercivity (Hc) values of 17 132 Oe and 3364 Oe with excellent remanent magnetization (Mr) values of 76.0 and 61.05 emu g−1 at 10 K and room temperature were obtained for CF-4 NPs (∼35 nm). The excellent remanent magnetization and high coercivity of CF-4 NPs led to a high energy product (BH)max of 2.41 MGOe (19.2 kJ m−3) at room temperature, which is the highest reported value to date for CoFe2O4 NPs to the best of our knowledge. The excellent magnetic properties indicated the capabilities of CoFe2O4 NPs in permanent magnets for current technological applications.