Composition and frequency dependent dielectric properties of Li-Mg-Ti ferrites

The frequency and composition dependent properties of mixed Li0.5MgxTixFe2. 5-2xO4 (where x=0.1, 0.2, 0.3, 0.4, 0.5 and 0.6) ferrites have been measure d at room temperature. The compositional variation of resistivity and diele ctric constant indicates the inverse trends with each other. The sample wit h x=0.4 shows lowest resistivity and highest dielectric constant. The ac re sistivity (rho(ae)), dielectric constant (epsilon'), dielectric loss tangen t (tan delta) and loss factor (tan delta/mu(i)) of all the samples decrease with increase in frequency exhibiting normal ferrimagnetic behaviour. The sample with x=0.4 shows a maximum at around 1 kHz in the tan delta versus f requency variation. The values of initial permeability (mu(i)) are independ ent of frequency. The saturation magnetization (Ms) values of the samples a re low and decrease with increase in x due to magnetic dilution by Mg2+ and Ti4+ ions. All the observed variations are explained on the basis of Fe2+/ Fe3+ ionic concentration as well as the electronic hopping frequency betwee n Fe2+ and Fe3+ ions in the present samples. (C) 2000 Published by Elsevier Science S.A.