Because of its broad range of functional applications,numerous kinds of perovskite-structured ceramics have been widely studied. However, the properties of barium iron tantalate, Ba(Fe1/2Ta1/2)O3 (BFT),which has a perovskite structure is not well known and only few studies have been performed. In the late 1950s, Galasso et al. [1] reported that the crystal structure of BFT is cubic perovskite and the lattice parameter is about a = 4.056A ° .An interesting phenomenon quoted in the paper is that the BFT showed
ferroelectric properties even though it has a cubic perovskite structure. On the other hand, an ambiguous dielectric characteristic of BFT was reported by Agranovskaya representing only a large dielectric loss tangent above 1 with no further explanation. Later,more detail crystal structure analyses in BFT showed that it had a cubic symmetry that can not possess ferroelectric properties.
The dielectric loss properties of Ba(Fe1/2Ta1/2)O3(BFT) ceramics, which has B-site disordered cubic perovskite structure were analyzed as functions of temperature and frequency. A dielectric loss relaxation peak in the vicinity of room temperature was observed and several assumptions were considered to explain the Debye-like dielectric loss relaxation phenomena in BFT. The dielectric loss relaxation process in BFT takes place by random electrical field or polarization fluctuation from the B-site cation valence mismatch in BFT crystal. Moreover, the very low pre-exponential factor for the relaxation times (s0f10 7 s) also supports the assumption of ionic thermal motion.