Mössbauer studies of spinellides of Mg(FeXCr2-X)O4 system obtained by the hydroxide co-precipitation method

Autor: Volodymyr Moklyak, S. I. Yaremiy, Ivan Gasyuk, I. P. Yaremiy, Anna Luсas, Mykola Matkivskyi
Rok vydání: 2017
Předmět:
Zdroj: Eastern-European Journal of Enterprise Technologies. 5:56-63
ISSN: 1729-4061
1729-3774
DOI: 10.15587/1729-4061.2017.112271
Popis: To establish regularities in formation of the magnetic microstructure in magnesium ferrite-chromites by the method of co-precipitation of hydroxides from chlorides of corresponding salts, ferrite spinels were synthesized with Mg(Fe x Cr 2-x )O 4 composition. It was found by the method of X-ray diffraction analysis that the resulting spinel occupies an intermediate position between normal and inverse spinels. Substitution of chromium for a part of trivalent iron ions in the spinel phases leads to normalization of the spinel structure. The magnetic microstructure of the resulting samples, distribution of iron among sublattices and presence of Fe 2+ ions were investigated by the method of Mossbauer spectroscopy. It was established that the magnetically ordered phase is only present in samples with x>1.6. Due to the non-high sintering temperature, low symmetry of the near surrounding and continuous distribution of effective magnetic fields on the Fe 3+ nuclei were observed in the samples. Analysis of the results of Mossbauer and X-ray structural studies has shown deviation of the real near surrounding of the iron ion from the most probable surrounding. No Fe 2+ ions were detected by the Mossbauer method in these samples. There is a good agreement in the relation between population of the iron ions among octahedral and tetrahedral sublattices (2.0) found by methods of X-ray and Mossbauer analysis. The obtained information confirms significant dependence of the properties of ferrite-spinels on the features of synthesis and shows necessity of checking the sample characteristics during changes or modifications in the production methods.
Databáze: OpenAIRE