Mössbauer study of relaxation phenomena in zinc-ferrous ferrites

The M\"ossbauer spectra for the ZnₓFe_3-xO₄ system have been studied for x=0, 0.2, 0.4, 0.6, and 0.8 at 77 and 300^∘{}K. For $x>0.2$, the room-temperature spectra show relaxation effects similar to other zinc-substituted ferrite systems such as Ni-Zn and Co-Zn. As this effect occurs at temperatures far from the N\'eel temperature it cannot be accounted for by the critical point fluctuations in the spin system. Simultaneous study of magnetic relaxation has shown that the relaxation effects in the M\"ossbauer line shape arise owing to the domain-wall displacements. The line shape has been computed using Blume and Tjon's analysis of the M\"ossbauer spectra in a fluctuating environment and agreement with experimental data was found to be satisfactory. The variation of hyperfine field with zinc concentration has been explained qualitatively on the basis of supertransferred hyperfine interactions.