The electrical properties, shrinkage, porosity and X-ray diffraction analysis for Mg-Ti ferrite of the general formula Mg 1+ xTixRyFe2 � 2xyO4; x=0.5, y=0, 0.025 and R=(Nd, Gd and La) were studied. The investigated samples were crystallized in the spinel phase. The measurements of the electrical properties were carried out at different temperatures (295- 750 K) as a function of the applied frequency (50-1000 kHz). The experimental results show that the rare earth ions initiate new sites called dodecahedral (C-sites) and at the same time increase the valence exchange between the different metal ions existing in the different sites. This behavior takes place at certain concentrations of the rare earth ions. The low rare earth concentration as well as the high sintering times (100 h) leads to an inflection in the electrical properties. Verwey conduction mechanism and hopping are used to interpret the conductivity of the samples. D 2003 Elsevier Science B.V. All rights reserved.
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