⁵⁷Fe Mössbauer and infrared studies of the system Co_1−x Cd _x Fe₂O₄

Abstract

Mössbauer and infrared studies were made on samples of the ferrite system Co_1−xCd_xFe₂O₄ x=0.0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1. Mössbauer spectra were taken at room temperature. The spectra of the samples withx≤0.7 showed well defined Zeeman patterns and they have been analyzed with two components, one due to A-site Fe³⁺ ions, and the other due to B-site Fe³⁺ and Fe²⁺ ions. The pattern due to B-site appeared to be composite and an explanation is given. The spectra withx=0.9 and 1 showed only a quadrupole splitting. The effect of cadmium substitution on the various hyperfine interactions has been discussed and the cationic distribution has been deduced for all values ofx. Far infrared spectra of the ferrite samples in the range 200–700 cm⁻¹ were reported. Four bands were observed: the high frequency bandv ₁ is assigned to tetrahedral complexes, and the low frequency bandv ₂ to octahedral complexes, a small bandv ₃ is due to Co²⁺-O²⁻ complexes andv ₄ is assigned to the lattice vibration of the system. The splitting occurred in thev ₁ andv ₂ bands atx=0.9 and inv ₂ atx=1, indicating the presence of Fe²⁺ ions in octahedral sites.