Synthesis and size-dependent magnetic properties of single-crystalline hematite nanodiscs

Single-crystalline α-Fe2O3 nanodiscs with diameters of 132–150 nm were synthesized by a facile and efficient hydrothermal reaction of FeCl3 with NaH2PO4 and H2O at 200 °C for 12 h. The diameters of the nanodiscs can be decreased to 91–112 and 78–92 nm by adding ethanol glycol into the hydrothermal system. The α-Fe2O3 nanodiscs are formed by the cooperative action of selective adsorption and etching of the phosphate ions. The as-synthesized α-Fe2O3 nanodiscs exhibit weak ferromagnetic behaviours. The remanent magnetization and coercivity of the nanodiscs with the diameters of 132–150 nm are 0.01743 emu g−1 and 214.8 Oe, respectively, and the remanent magnetization and coercivity decrease with deceasing the nanodisc size.

► Single-crystalline α-Fe2O3 nanodiscs are synthesized via the hydrothermal reaction of FeCl3, NaH2PO4 and H2O. ► The nanodisc diameters can be decreased by adding ethanol glycol into the hydrothermal system. ► The nanodiscs are formed by the cooperative action of selective adsorption and etching of the phosphate ions. ► The α-Fe2O3 nanodiscs exhibit weak ferromagnetic behaviours, and their Mr and Hc decrease with a size reduction.