Doping magnesium ion to tune electrical and dielectric properties of BaCo2 hexaferrites

Pure BaCo2 W-type hexaferrites i.e. BaCo2-xMgxFe16O27 (x <= 1) have been synthesized by the chemical co-precipitation method at 1223 K and have been investigated for their structural, electrical and dielectric properties. The X-ray diffraction (XRD) patterns conformed to the standard single phase of the hexagonal W-type structure. We examined the surface morphology of the prepared samples by the use of scanning electron microscopy (SEM) analysis. The dc-electrical resistivity (rho) measurements showed metal to semiconductor transition (TM-S), in a temperature range of 298-663 K. The maximum, at which the TM-S occurs, varies with the magnesium concentration in the samples. Crystallographic distribution of Mg2+ cations was responsible for the variation in the overall resistivity (rho) pattern of BaCo2-W type hexaferrites. The dielectric constant (epsilon') and the dielectric loss (tan delta) measurements at room temperature showed normal behavior of hexaferrites. The obtained results indicated that the Mg2+ ions played an important role in the tuning of the electric and the dielectric properties of BaCo2-W hexaferrites, which might have possible applications in transformer cores to reduce the eddy current losses. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.