Mössbauer Resonance of 57Fe in Oxidic Spinels Containing Copper and Iron

The Mossbauer resonance of 57Fe in tetragonal and cubic phases of the spinel copper ferrite (CuFe2O4) has been investigated between 4.2° and 1000°K. Complementary experiments have been performed on the spinel systems Cu1−xZnxFe2O4 and Cu1−xCdxFe2O4, with O≤x≤0.5. At 4.2°K, at least two nonequivalent six‐line patterns, I and II, are resolved in the spectra of all phases, exhibiting a combined magnetic and electric hyperfine interaction. The isomer shifts, internal magnetic fields, and nuclear quadrupole splittings have been determined as a function of temperature. At higher temperatures, below the Neel point, the cubic phases show an apparent six‐line pattern with lines of non‐Lorentzian shape and unusually broad half‐widths. Above the Neel temperature, a distinct electric quadruple splitting was observed in the spectra of the tetragonal phases while the cubic phases show an apparent one‐line pattern of a complex shape.