Evidence of ferrimagnetic ordering in FeMnO3 produced by mechanical alloying

Mechanical alloying of alpha-Fe2O3 with Mn2O3 is shown to produce FeMnO3, w hose X-ray diffraction pattern fits the cubic structure (space group Ia3. l attice constant, approximate to 9.40 Angstrom) identical to that of Mn2O3. Tempcrilture variation of its magnetic susceptibility chi shows a phase tra nsition near T-c approximate to 40 K and the chi(-1) versus T data for T > T-c fit the variation expected for a ferrimagnet with a magnetic moment of 2.8 mu(B) per formula unit. The Mossbauer spectrum for T > T, is a doublet with quadrupole splitting approximate to 1 mm/s and isomer shift approximat e to 0.4 mm/s, changing to a sextet for T < T-c with a hyperfine field of 4 45 kOe at 16 K. (C) 2000 Elsevier Science B.V. All rights reserved.