MAGNETIC AND MOSSBAUER STUDIES OF TI4-SUBSTITUTED SOFT MN-ZN FERRITES()

The present work reports the magnetic properties and Mossbauer spectra of soft ferrites MnaZnbFe1-a-b2+Fe23+O4 with Ti4+ substitutions. The addition of Ti4+ to manganese-zinc ferrites induces considerable impro vements of properties such as the linear dependence of permeability ve rsus temperature, and small disaccommodation of the permeability. Samp les with Mn0.57Zn0.34Fe0.09+x2+TixFe2-2x3+O4 composition (where x = 0. 00, 0.02, 0.04, 0.06, 0.08, 1.00) were prepared by the usual ceramic t echnology. The presence of Ti ions strongly influences the magnetic an isotropy, as evidenced by the temperature dependence of the permeabili ty. A sublattice assigned to Ti4+Fe2+ pairs appeared in the Mossbauer spectra, which also gave information on the local surroundings of iron ions. The appearance of a secondary maximum of permeability (SMP) at negative temperatures or a constant slope over a wide temperature rang e is typical for mu(i)(t) curves. Increasing Ti4+ contents shift the S MP to higher temperatures because of a positive contribution to K1 of the Ti4+Fe2+ pairs at octahedral sites, in agreement with the hyperfin e magnetic fields observed for ferrites with large titanium substituti ons.