Identification of a Super Paramagnetic Phase of Titanium Substituted Mn-Zn Ferrites and Its Magnetic and Mossbauer Studies

The magnetic and Mossbauer studies were carried out in Mn0.8+x Zn0.2TixFe2-2xO4 with x=0.10, 0.15, 0.20.The addition of Ti4+ induces considerable improvements of properties such as linear dependence of permeability versus temperature, Curie temperature, isomer shift, hyperfine interactions etc. Samples with Mn0.8+x Zn0.2TixFe2-2xO4 for x=0.10, 0.15, 0.20 were prepared by usual solid-state reaction method. To achieve equilibrium between the magnetic and core loss properties Titanium is introduced into the base composition of MnZn ferrite. A sublattice assigned to Ti4+Fe2+ pairs appeared in the Mossbauer spectra gave information on the local surroundings of iron ions. Increasing of Ti4+ shifts secondary maximum of permeability (SMP) to higher temperatures is in agreement with the hyperfine magnetic fields observed. The hyperfine magnetic field and electric quadrupole splitting decreases with the addition of Ti. The conduction mechanism is due to hopping of small polarons between Fe2+ and Fe3+.