Relationship between the dielectric properties and the conductivity of Ba ₂FeNbO ₆

In the present work, we performed detailed investigation on the relationship between the dielectric properties and the conductivity of Ba ₂FeNbO _6. Our results revealed that (1) the colossal dielectric behavior of the sample can be well understood based on the framework of universal dielectric response, (2) the observed relaxation shows a distinct deviation from the Arrhenius behavior, and (3) the peak intensity of dielectric loss can be well expressed by a relation similar to the Fermi-Dirac distribution function rather than a thermally activation relation. These are the typical features for the hopping motions of polaronic carriers demonstrating that the dielectric properties and the conductivity of Ba ₂FeNbO ₆ are closely linked.