MnZn-ferrite has been prepared via high-energy ball milling of elemental oxides MnO, ZnO, and α-Fe2O3. Neutron diffraction measurements suggest a high density of vacancies in a spinel structure. The spinel phase appears to comprise 99.8 wt % of the material in the sample milled for 40 h, with the remainder attributable to unreacted α-Fe2O3. The x-ray absorption near-edge structure was analyzed to provide an understanding of the charge state of the constituent Fe ions. This analysis reveals about 2/3 of Fe cations to be trivalent, increasing to about 3/4 after a 5 h anneal at 450°C. The heat treatment is also observed to induce a cation redistribution in the ball-milled ferrite toward that of a standard processed via ceramics methods. Results from Mössbauer spectroscopy determine the average hyperfine fields in the sample milled 40 h to be 289 and 487 kOe at 295 and 78 K, respectively. The average isomer shift is 0.32 mm/s at 295 K and 0.46 mm/s at 78 K, values which are typical of iron (III) in a spinel oxide lattice. As expected for a cubic-like environment, the quadrupole shifts are very small, ranging from 0.07 mm/s at 295 K to 0.00 mm/s at 78 K.
D. J. Fatemi et al., "X-Ray Absorption, Neutron Diffraction, and Mössbauer Effect Studies of MnZn-Ferrite Processed through High-Energy Ball Milling," Journal of Applied Physics, vol. 85, American Institute of Physics (AIP), Jan 1999.
The definitive version is available at https://doi.org/10.1063/1.369114
Materials Science and Engineering
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© 1999 American Institute of Physics (AIP), All rights reserved.
01 Jan 1999