Fabrication and Characterization of the Plate-Shaped γ-Fe₂O₃ Nanocrystals

Plate-shaped γ-Fe 2 O 3 nanocrystals have been successfully prepared in a water system by a simple reduction−oxidation method at room temperature and under ambient pressure. The reactions contain two steps: first, Fe(II) is reduced into Fe atoms by γ-ray irradiation in nitrogen atmosphere; then, Fe atoms are oxidized into γ-Fe 2 O 3 in air. XRD, TEM, EDXA, XPS, and Mössbauer spectrum were used to characterize the final product. The magnetic characterization showed that the γ-Fe 2 O 3 nanocrystals have a specific saturation magnetization of 83 emu/g and a coercivity of 320 Oe (25.5 kA/m). A possible formation mechanism of the plate-shaped γ-Fe 2 O 3 nanocrystals was suggested.