Self-assembly of magnetite mesocrystal microdisks with hierarchical architectures

A simple electrochemical corrosion synthesis route using hot and concentrated alkaline aqueous solution is demonstrated for the first time to fabricate high yield crystalline magnetite mesocrystal microdisks without adding any organic additives. According to the results of time-dependent experiments, the self-assembly mechanism of mesocrystals is revealed as crystallization–dissolution–recrystallization. The mesocrystals with large sizes of 30 μm show hierarchical architectures. They are piled up with several thin layers and each layer is composed of small nanoparticles with an average size of 20 nm. Moreover, room temperature ferrimagnetic behavior with large coercivity value of 182.88 Oe (∼0.01829 T) is recorded.