Mössbauer and XRD Studies of N0.6Cu0.2Zn0.2Ce(x)Fe2-xO4 Ferrites by Sol-Gel Auto-Combustion.

In this work, stoichiometric Ni0.6Cu0.2Zn0.2Ce(x)Fe2-xO4 ferrites with 0 ≤ x ≤ 0.85 have been prepared by Sol-Gel auto-combustion method and we have investigated the effect of impurity CeO2 phase to the microstructure and hyperfine magnetic field in spinel ferrite. The results of XRD patterns confirm that the average crystallite size of samples decreases with Ce3+ substitution increasing and the lattice parameters vary as a function of x content. 57Fe Mössbuaer spectra at room temperature for all samples confirm the [Fe(3+)-O2-Fe3+] super exchange interaction decrease due to cerium substitution. For low temperature auto-combustion samples it reveals one normal sextet line and one doublet line x ≤ 0.25, which show well-resolved ferromagnetic order. Lattice defects are determined and Mössbuaer spectrums vary from magnetic sextet to relaxation doublet at x > 0.45 due to a mass of CeO2 phase. In contrast, the Mössbuaer spectra for the samples sintered at 800 °C/3 h detect the secondary phase-Fe2O3 where the cation distribution occurs and it collapses to paramagnetic doublet (x ≥ 0.85). So Ce3+ substitution has its maximum limit values of super exchange interaction and high sintering temperature will affect this interaction. SEM shows the crystallite of the un-doped specimen sintered at 800 °C/3 h form well.