Metal ion-mediated synthesis and shape-dependent magnetic properties of single-crystalline α-Fe2O3 nanoparticles

Abstract

A facile and effective hydrothermal process for the controllable synthesis of uniform single-crystalline hematite (α-Fe₂O₃) nanoparticles with different shapes is presented. The morphology of the α-Fe₂O₃ products can be controlled through simply adjusting the metal ions additive. The effects of the different metal ions (atomic number from 25–30) on the size and morphology of the products were investigated. The cubic and thorhombic α-Fe₂O₃ particles can be generated by adding zinc ions and copper ions to the reaction mixture, respectively. For providing some insight into the correlation between the morphology and physicochemical properties, the magnetic properties of the as-obtained cubic and thorhombic α-Fe₂O₃ products were investigated. Interestingly, the cubic α-Fe₂O₃ products exhibited a superparamagnetic properties at T = 300 K. In contrast, the thorhombic α-Fe₂O₃ products displayed ferromagnetic and low-temperature phase transition behaviours at room temperature. The fundamental understanding of crystal-phase and morphology-tunable nanostructures that are enclosed by shape-dependent magnetic properties is expected to direct the design and development of highly efficient magnetic nanomaterials.