FE-57 MOSSBAUER-SPECTROSCOPY OF ZINC FERRITE PREPARED BY A VARIETY OFSYNTHETIC METHODS

Confirmation of the suggestion of B site Zn2+ in nanocrystalline ZnFe2 O4 has been sought through X-ray diffraction, Fe-57 Mossbauer spectros copy, magnetic susceptibility and TEM measurements on bulk and nanocry stalline samples prepared by different techniques. Measurements on bul k samples are in agreement with previously reported ones. Samples prep ared at low temperature from solutions of salts exhibit broadened XRD patterns, susceptibilities 4-5 times that of bulk samples, broadened M ossbauer spectra and particle sizes between 5-20nm. Low-impact, ball-m illed bulk samples exhibited properties similar to the low temperature , nanocrystalline samples. At 298K, the Mossbauer spectra exhibit no m agnetic hyperfine splitting and no evidence for a significant proporti on of A site Fe3+ ions. The unusually high susceptibilities appear to result mainly from the decreased particle size and not from profound c hanges in the cation distribution of a well-defined, spinel structure.