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 measured at room temperature. The compositional variation of resistivity and dielectric constant indicates the inverse trends with each other. The sample with x=0.4 shows lowest resistivity and highest dielectric constant. The ac resistivity (ρac), dielectric constant (ε′), dielectric loss tangent (tan δ) and loss factor (tan δ/μi) 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 δ versus frequency variation. The values of initial permeability (μi) are independent of frequency. The saturation magnetization (Ms) values of the samples are 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 between Fe2+ and Fe3+ ions in the present samples.