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Infrared Spectra of Cubic and Tetragonal Manganese Ferrites
Author(s) -
Brabers V. A. M.
Publication year - 1969
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.19690330209
Subject(s) - manganese , tetragonal crystal system , octahedron , ion , infrared spectroscopy , crystallography , crystal structure , chemistry , infrared , spectral line , absorption spectroscopy , lattice constant , analytical chemistry (journal) , materials science , physics , chromatography , quantum mechanics , diffraction , optics , organic chemistry , astronomy
The infrared absorption spectra in the range from 200 to 700 cm −1 of cubic and tetragonal manganese ferrites, Mn x Fe 3– x O 4 , are reported. An analysis of the spectra is made with a model by which the lattice vibrations are classified into species of the point group D 2 d on the analogy of the results for gas molecules of equivalent symmetry. For cubic spinels with manganese concentrations x ≦ 1.0 the classification can be made according to the model of Waldron into the species of the point group T d . However, at 335 cm −1 an absorption has been observed which is out of the scope of the T d or D 2 d classification, and which is caused by the substitution of a part of the octahedral Fe 3+ ions by Mn 2+ ions. The IR spectra of manganese ferrites with compositions 1 < x ≦ 3 can be analysed with the D 2 d classification. The spectra of these materials do not change suddenly with the manganese concentration or with the crystal structure. From the splitting of the absorption bands in cubic ferrites with x > 1 it is concluded that there are local tetragonal distortions originating from the Jahn‐Teller effect of the octahedral Mn 3+ ions.