Crystal Chemistry and Magnetic Properties of Polycrystalline Spinel Ferrites Li0.33Fe2.29Zn0.21Mn0.17O4

AbstractPolycrystalline spinel ferrites of composition Li0.33Fe2.29Zn0.21Mn0.17O4 have been synthesized by the ceramic method at sintering temperatures of 950, 1000, 1050, and 1100°С. The crystal structure of the resulting samples has been studied by X-ray powder diffraction, and the chemical composition of the ferrites has been refined by the secondary ion mass spectrometry. Magnetic characteristics of the samples have been measured on an MK-3E magnetic measuring device. Room-temperature Mössbauer spectra have been recorded on an Ms-1104 Em spectrometer. The cation distribution in the crystal lattice of the resulting ferrites has been established; crystal chemical formulas have been calculated for each sintering temperature. The Mössbauer spectra of all the obtained samples are modeled by five sextets, which is explained by the appearance of nonequivalent Fe3+ ions in octahedral and tetrahedral positions, differing in the composition of the second coordination sphere. Combinations of lithium, manganese, and zinc ions in the nearest cationic environment of octahedral iron ions have been determined on the basis of a model that takes into account the peculiarities of changes in the Mössbauer parameters with an increase in the sintering temperature of ferrites. It has been shown that Mössbauer spectroscopy in combination with X-ray powder diffraction and magnetometry provides efficient control of the phase composition, cation distribution, and magnetic properties in substituted ferrites.