Electrical properties and initial permeability of Cu-Mg ferrites

A series of polycrystalline spinel ferrites with composition Cu1-xMgxFe2O4 where 0.0 <= x <= 1 are prepared by the standard ceramic method. The single-phase cubic spinel structure of all the samples has been confirmed from X-ray diffraction analysis. The lattice constant increases linearly with increasing magnesium content obeying Vegard's law. The electrical properties (epsilon', and sigma) of the prepared samples are measured at different temperatures as a function of applied frequency ranging from 100 kHz up to 5 MHz. The general trend of epsilon', and sigma is decreased with increasing Mg2+ and increases with increasing temperature. The observed variation of dielectric properties is explained on the basis of Cu2+/Cu1+ ionic concentration as well as the electronic hopping frequency between Fe2+ and Fe3+ ions in the present samples. The data of initial permeability is also discussed. (C) 2014 Elsevier Masson SAS. All rights reserved.