Dielectric and electrical properties of Bi9Fe5Ti4O29 nanoceramics

Bi9Fe5Ti4O29 nanoceramic was prepared by a high-temperature solid-state reaction technique. A preliminary X-ray structural analysis exhibited the formation of single-phase compound with an orthorhombic structure. SEM micrograph of the material showed the plate and rod shaped grains distribution throughout the sample. The dielectric and electrical properties of Bi9Fe5Ti4O29 were investigated in a wide frequency range (100 Hz–1 MHz) at different temperatures (30–500 °C) by complex impedance spectroscopy. Detailed analysis of impedance spectra showed that the electrical properties of the material are strongly dependent on frequency and temperature. A dielectric anomaly was observed at 296 °C, which is related to ferroelectric–paraelectric phase transition. The existence of ferroelectric properties at room temperature (much below 296 °C) was confirmed by appearance of hysteresis loop with a small polarization (i.e., 2Pr = 0.018 μC/cm2). Studies of the ac and dc conductivity over a wide range of temperature provided the activation energy in the range of 0.45–1.67 eV, and a significant variation in conduction mechanism of the compound was observed.