Structural and magnetic properties of NiZn ferrites prepared by microwave sintering

A series of ferrites was prepared using microwave sintering, starting with both hematite and magnetite precursors in the Ni1-xZnxFe2O4 (x=0-1) system. X-ray diffraction measurements were performed to yield the lattice constant as function of the amount x of Zn substitution. For both hematite and magnetite series, the lattice parameter was found to increase with increasing x. Moessbauer spectroscopy was performed at room temperature and spectra were analyzed using the binomial distribution. The hyperfine magnetic field of the octahedral sublattice was found to decrease with increasing the number of Zn nearest neighbors for all values of the substitution level. The area of the tetrahedral sublattice decreases with increasing x and the sublattice area of the octahedral sites increases correspondingly for both series of samples, as a result of substitution of iron by zinc in the tetrahedral sites. The hyperfine magnetic field of the tetrahedral sublattice was found to decrease as function of Zn amount x, for both hematite and magnetite series. However, in most cases, the hyperfine magnetic fields for the magnetite series are slightly less than those corresponding to the hematite series