Influence of Axial Pressure on Electric Properties of Na_0.5Bi_0.5TiO₃-PbTiO₃System

Abstract

The temperature dependence (30-500 • C) of electric permittivities of Na 0.5 Bi 0.5 TiO 3 -PbTiO 3 system under mechanical load (0-1.5 kbar) has been investigated. The hysteresis loops have been also measured. It is found that external stress significantly influences the dielectric and ferroelectric properties. This influence is connected with: (i) the shift of phase transition, suppressing the dielectric dispersion, diffuseness of permittivity characteristics, and reduction of the thermal hysteresis, and (ii) decrease in field-polarization hysteresis. The results were discussed in terms of domain walls, large polarizability of Pb +2 and Bi +3 ions and internal stresses. The results were compared with the data for pure Na 0.5 Bi 0.5 TiO 3 . The electrostrictive coefficients, latent heats and corresponding entropy changes of phase transformation were also calculated.

New Na0.5Bi0.5TiO3–NaTaO3‐Based Perovskite Ceramics

“…Therefore, an axial stress that is not comparable with the coercive field at room temperature can move the domain walls, but does not switch the polarizations. On the other hand, at higher temperatures, this stress becomes comparable with the coercive field, which increases its influence on the permittivity 29,34 …”