Some ac electrical properties of Li-Mg ferrites

The ac resistivity (rho(ac)), dielectric constant (epsilon'), dieiectric lo ss tangent (tan delta) and initial permeability (mu(i)) of mixed Li0.5-x/2M gxFe2.5-x/2O4 (where x = 0.1, 0.2, 0.3, 0.4, 0.5, and 0.6) ferrite system w ere measured at room temperature as a function of frequency in the range fr om 1 kHz to 1 MHz. The resistivity of all the samples decreased with increa se in frequency, indicating that the samples exhibited normal ferrimagnetic behavior. The compositional variation of resistivity and dielectric consta nt indicated the inverse trends of each other. The sample with x = 0.3 show ed the lowest resistivity and the highest dielectric constant. The dielectr ic loss tangent showed maxima at 3 kHz for x = 0.2 samples and at 15-20 kHz for x = 0.3 and 0.4 samples. All of the variations are explained on the ba sis of Fe2+/Fe3+ ion concentration on octahedral sites as well as the elect ronic hopping frequency between Fe2+ double left right arrow Fe3+ ions. (C) 1999 Elsevier Science Ltd.