Evidence of ferrimagnetic ordering in FeMnO3 produced by mechanical alloying

Mechanical alloying of α-Fe2O3 with Mn2O3 is shown to produce FeMnO3, whose X-ray diffraction pattern fits the cubic structure (space group Ia3, lattice constant ≈ 9.40 angstrom) identical to that of Mn2O3. Temperature variation of its magnetic susceptibility χ shows a phase transition near Tc ≈ 40 K and the χ-1 versus T data for T > Tc fit the variation expected for a ferrimagnet with a magnetic moment of 2.8 μB per formula unit. The Mossbauer spectrum for T > Tc is a doublet with quadrupole splitting ≈ 1 mm/s and isomer shift ≈ 0.4 mm/s, changing to a sextet for T < Tc with a hyperfine field of 445 kOe at 16 K.