Ferrimagnetic Ordering in FeMnO3 Produced by Mechanical Alloying.
Abstract
The stability of various compounds formed in the Fe-Mn-O system depends not only on Fe/Mn/O ratios but also on the method of preparation and on the calcination temperature. These compounds are of interest as ferrites in electronics and as catalysts. In this work mechanical alloying of α-Fe_2O3 with Mn_2O3 is shown to produce FeMnO_3. The x-ray diffraction pattern fits the cubic structure (space group Ia3, lattice constant ≈ 9.40 Åidentical to that of Mn_2O_3, with Fe replacing some of Mn atoms. Temperature variation of its magnetic susceptibility \chi shows a phase transition near Tc ≈ 40 K and the \chi vs T data for T > Tc fits the variation expected for a ferrimagnet with a magnetic moment of 2.8 μB per formula unit. The Mössbauer 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. *The author would like to acknowledge partial support from HUD special project grant #B 98 Sp MD 0074 and a grant from NASA, NASA-NAG-5-3508.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2000
- Bibcode:
- 2000APS..MARF36041S