Correlation between temperature dependent dielectric and DC resistivity of Cr substituted barium hexaferrite

The chromium substituted barium hexaferrite (BaFe₁₂O₁₉) crystallize to the hexagonal symmetry (P6₃/mmc space group), which has been studied by employing the XRD technique. The XRD analysis is supported by the Raman spectra and, microstructural analysis has been carried out by the FESEM (field emission scanning electron microscope) technique. Average particle size is found to be around 85 nm. Two peaks are observed in the temperature versus dielectric constant plots and, these two transition temperatures are identified as T _d and T _m. The temperature T _d is due to dipole relaxation, whereas T _m is assigned as dielectric phase transition. Both T _d and T _m increase with the increase in frequency. However, the former one (i.e. T _d) increases more rapidly compare to that of later one (i.e. T _m). Both the temperature (T _d and T _m) are also well identified in the temperature dependent DC resistivity. All the samples exhibit the negative temperature coefficient of resistance (NTCR) behavior, which reveals the semiconducting behavior of the material. The Mott VRH model could explain the DC electrical conductivity. Both dielectric constant and DC resistivity is well correlated with each other to explain the transport properties in Cr³⁺ substituted barium hexaferrite. (paper)