A facile synthesis of magnetite single-crystal particles by employing GO sheets as template for promising application in magnetic fluid

It was reported a facile strategy to fabricate magnetite (Fe₃O₄) single-crystal particles with critical single-domain size by employing graphene oxide (GO) sheets as template. In this method, the small-sized Fe₂O₃ nanoparticles were first synthesized, and then low-temperature annealing under H₂ would convert them into large-sized Fe₃O₄ single-crystal particles. The synthetic particles with an average size of 100 nm exhibit high saturation magnetization (M_s) of 0.085 A·m²·g⁻¹, which is very close to theoretical value, being among the highest values in ever reported for Fe₃O₄ made from chemical methods. On this basis, the small-sized Fe₃O₄ particles (average size of 30 nm) were also fabricated by coating with Na₂CO₃ shell.