Microstructure, electrical properties and Hall coefficient of europium-doped Li-Ni ferrites

Europium-doped Li-Ni soft ferrites with the general formula of (Li0.5Fe0.5)(0.5) Ni0.5EuyFe2-yO4 (where 0 <= y <= 0.1), were prepared by using powder processing technique. The effect of Eu addition on the AC and DC electrical resistivity, Hall coefficient, charge mobility and charge carrier concentration of the prepared ferrites were characterized at room temperature. Seebeck coefficient was also calculated from the carrier concentration. Hall and Seebeck coefficients confirmed that all of the prepared samples are p-type semiconductors. The formation of the single-phase spinel ferrites structure was verified by X-ray diffraction. Lattice parameter, X-ray density, apparent density and A- and B-sites radii were calculated. The microstructure, which plays an important role in determining electrical properties, was analyzed by scanning electron microscopy and EDS, and found to have a major effect on the electrical properties. The dielectric loss was calculated from the AC conductivity and found to increase with firing temperature. This study provides information to optimize the composition and microstructure of the europium-doped Li-Ni ferrite with desired performance. (C) 2009 Elsevier B.V. All rights reserved.