Excellent temperature stability of piezoelectric properties in PbNb₂O₆‐based ceramics up to 450°C

Abstract

Dense (Pb_0.92Ba_0.08)Nb₂O₆‐xmol% MnO₂ with 0.25 wt% TiO₂ ceramics with a single orthorhombic phase were synthesized through a conventional solid‐state reaction method. Excellent piezoelectric performance (d₃₃ = 90 pC/N) and low dielectric loss (tan δ = 0.5%) are achieved in Mn‐doped samples. Interestingly, the dielectric anomalies are observed in the temperature range of 300–400°C, which could be completely suppressed through Mn doping. The dielectric anomalies are associated with thermally activated domain wall motion, which could be constrained by the defect dipoles produced by Mn doping. More importantly, all samples experience about 12% performance degradation below 300°C, attributed to an accelerated aging process at elevated temperatures. After thermal aging, the samples exhibit excellent performance stability within the temperature range of 25–450°C, showing no further degradation. The results indicate that the PbNb₂O₆‐based ceramics are promising high‐temperature piezoelectric materials for piezoelectric devices operating at temperatures up to 450°C.