Structural and Electrical Performance of (Bi1/2Ba1/4Sr1/4)(Ti1/2Fe1/2)O3Relaxor

Highlights: • Relaxor –type ferroelectric behaviour of 0.5BF-0.5BST with diffused type phase transition is studied. • Tetragonal phase stability with balanced oxygen stoichiometry as well as pseudocubic symmetry is confirmed. • High dielectric constant, low loss, slight relaxor behavior, less leakage current enhances the appliance of the material. • Grain, grain-boundary, leakage, energy gap (0.93 eV) and NTCR (Thermistor like) property have been studied. • Charge carriers are found to obey different conduction mechanisms through the potential barrier. -- Abstract: The polycrystalline sample of a ternary system of 0.5BF-0.25ST-0.25BT (i.e., Bi_0.5Ba_0.25Sr_0.25)(Ti_0.5Fe_0.5)O₃ was prepared via a conventional high-temperature solid-state reaction technique. The preliminary structural analysis using room temperature X-ray diffraction (XRD) data shows the tetragonal as well as pseudo-cubic nature of the compound. Analysis of temperature and frequency-dependent dielectric parameters, obtained in a wide range of temperature and frequency, exhibits diffused phase transition with relaxor-ferroelectric nature of the material. This observation has been confirmed through temperature and frequency evolved P-E loops. The sample is free from impurities and is structurally stable. The Vogel-Fulcher plot was used to confirm the relaxor type of ferroelectric behavior of the material. The dielectric relaxation, grain, grain-boundary contribution, and semiconductor (negative temperature coefficient of resistance) nature of the compound have been analysed through impedance analysis. The current-voltage (I-V) and leakage characteristics confirm the bulk limited (SCLC) and interface limited (Schottky, Poole-Frankel emitted and Fowler-Nordheim type) conduction mechanisms. The energy bandgap, calculated from the I-V-spectra, is found to be 0.93 eV in the particular (high) temperature range indicating the semiconducting nature of the material.