Na[Formula: see text]Bi[Formula: see text]TiO3-0.06BaTiO3 relaxor ferroelectrics (RFEs) ceramic samples were investigated by means of dielectric and acoustic emission methods in the temperature range of 70–350[Formula: see text]C and in dependence on frequency. Dielectric curve exhibits two anomalies: strongly dispersive the local maximum, within 130–180[Formula: see text]C and slightly dispersive the smeared high-temperature maximum within 300–310[Formula: see text]C. Acoustic emission exhibits the five groups of bursts: near 123[Formula: see text]C, 150–180[Formula: see text]C, near 225[Formula: see text]C, 300–310[Formula: see text]C and 327[Formula: see text]C. The first and third groups of acoustic emission bursts correspond to phase transitions of R[Formula: see text]c-P[Formula: see text]bm phases coexisting in this temperature, range, while the fourth and fifth groups of acoustic emission bursts correspond to P[Formula: see text]bm-P[Formula: see text] /mbm-Pm[Formula: see text] m phase transitions. The second group of acoustic emission bursts corresponds to strongly dispersive local maximum at which no phase transition has been proved in Na[Formula: see text]Bi[Formula: see text]TiO3-0.06BaTiO3. The existence and the location of the intermediate temperature, [Formula: see text], in Na[Formula: see text]Bi[Formula: see text]TiO3-0.06BaTiO3 compound are discussed.

[001] lead free relaxor ferroelectrics crystals of Na0.5Bi0.5TiO3–0.06BaTiO3 were studied by means of dielectric and acoustic emission methods in the temperature range of 25–240 °C and under a dc bias electric field up to 0.4 kV/cm. A temperature maximum of the dielectric constant was found near 170 °C, as well as the acoustic emission bursts pointed out to both the depolarization temperature near 120 °C and the temperature, corresponding to the maximum of dielectric constant, near 170 °C. While the depolarization temperature increased linearly, the temperature of the dielectric constant maximum was shown to exhibit a V-shape behavior under an electric field: it initially decreases, reaches a sharp minimum at some small threshold electric field of 0.15 kV/cm, and then starts to increase similar to the Curie temperature of the normal ferroelectrics, as the field enhances. Acoustic emission bursts, accompanying the depolarization temperature, weakened with the enhancing field, whereas the ones accompanying the temperature of the dielectric constant maximum exhibited two maxima: near 0.1 kV/cm and near 0.3 kV/cm. The meaning of these two acoustic emission maxima is discussed.

Na[Formula: see text]Bi[Formula: see text]TiO3–0.06BaTiO3 relaxor ferroelectrics ceramics samples, doped with 1[Formula: see text]wt.% of CuO, Fe2O3, Sb2O3, La2O3 and Ta2O5, were investigated. The grain structures were observed and corresponding piezomodulus [Formula: see text] were measured for all the compounds at room temperature. It was shown that the piezomodulus [Formula: see text] enhanced as the grain size increased, and in the same time, the piezomodulus [Formula: see text] weakened as the radius of incorporated ion enlarged. The mechanisms of such dependence of piezomodulus [Formula: see text] on both grain sizes and radii were discussed.

Na0.5Bi0.5TiO3-0.06BaTiO3 relaxor ferroelectrics ceramic samples doped with 1 wt% of CuO, Fe2O3, Sb2O3, La2O3 and Ta2O5 were investigated by means of dielectric and acoustic emission methods in the high-temperature range. Dielectric constants exhibited a wide and smeared maximum at the temperature Tm, accompanied by acoustic emission sharp bursts, but the dielectric constants exhibited no anomaly when further transiting into cubic paraelectric phase at the temperature Tp, accompanied by acoustic emission sharp bursts, too. Based on acoustic emission data the shifts of these two temperatures, Tm and Tp, in dependence on a wt% of the incorporated ions as well as the acoustic emission count rate distribution in dependence on the incorporated ions radii were plotted and discussed.