Mossbauer study of the Cu-Cd ferrite system

The magnetic properties of the Cd_xCu_1?xFe₂O₄ ferrite system (x = 0 to 1) have been investigated by means of Mossbauer Spectroscopy. Mossbauer Spectra for x = 0.0 to 0.6 suggest the existence of two hyperfine fields, one due to the Fe³⁺ tetrahedral ions (A-sites) and the other due to Fe³⁺ octahedral ions (B-sites), while for x = 0.7 it shows relaxation behaviour and for x ? 0.8 it exhibits a paramagnetic quadrupole doublet. The systematic dependence of the isomer shift, quadrupole interactions and nuclear fields of ⁵⁷Fe³⁺ ions in both A- and B-sites has been determined as a function of cadmium content. The variation of nuclear magnetic fields at the A- and B-sites are explained on the basis of A-B and B-B supertransferred hyperfine interactions. Analysis of the relaxation spectrum observed at x = 0.7 (300 K) suggests that the relaxation mechanism is due to domain wall oscillations. It has been found here that the QS increases from CuFe₂O₄ as the cadmium concentration is increased.