Electrical properties of SrBi2-yYyNb2-xVxO9 (x/y=0/0, 0/0.2, 0.05/0.1, 0.1/0.05 and 0.2/0) ceramics

The bismuth layer ferroelectric group has been extensively investigated for their use as high-temperature piezoelectric and as non-volatile ferroelectric memories, due to their high ferro-paraelectric phase transition temperature and their excellent fatigue strength. Ceramics made from strontium bismuth niobate (SrBi2Nb2O9) are promising alternatives to lead-based ceramics. The electrical properties of SrBi2-yYyNb2-xVxO9 (0 <= x <= 0.2 and 0 <= y <= 0.2) ceramics as a function of temperature and frequency have been investigated. The mechanism by which the overlapping large polaron tunneling model (OLPT) is the adequate model for this compound at wide-ranging temperatures. Measurement data are discussed using the variable range hopping (VRH) theory. Eventually, the behavior of the ceramic compound is fitted by VRH. The activation energy, obtained from the graph of sigma(DC) versus temperature, is quite close to the VRH hopping energy. This suggests that the oxygen vacancies may act as polarons. The relaxation mechanism is mainly dominated by the short-distance mobility of the charge carriers caused by the non-Debye process.

Automated summary

The bismuth layer ferroelectric materials have been studied for their potential applications in high-temperature piezoelectricity and non-volatile ferroelectric memories. Electrical properties of strontium bismuth niobate ceramics were investigated. The variable range hopping theory was found to be suitable for describing the behavior of the ceramic compound, suggesting the presence of oxygen vacancies acting as polarons. The charge carriers' short-distance mobility caused by the non-Debye process dominantly contributed to the relaxation mechanism.