Electrical conductivity and dielectric properties of Sr doped M-type barium hexaferrite BaFe12O19

Abstract

The Raman results showed that the intensity of the resonance band remains unchanged in Ba1 xSrxFe12O19 compared to the undoped compound (x ¼ 0) indicating that the polarizability did not change during the vibrations. The particle sizes, observed by TEM, are reduced from 228 nm to 176 nm with doping. Electrical conductance measurements show that all samples present semiconductor-like behaviors. The Maxwell–Wagner model explains why the alternating electrical conductivity of the samples doped with Sr is lower compared to that of the undoped sample. The Correlated Barrier Hopping (CBH) model dominates the conduction process for the BaFe12O19 sample, whereas the No overlapping Small Polaron Tunneling (NSPT) model dominates the conduction process for the Ba0.5Sr0.5- Fe12O19 sample. For SrFe12O19 the conduction is dominated by the NSPT model at temperatures below 240 K and by the CBH model above 240 K. The BaFe12O19 compound exhibits a giant dielectric constant (3 0) whose values reached 104 at low frequencies. This value is reduced to 150 in the Sr-doped hexaferrite.