Microscopic origin of the enhanced piezoelectric thermal stability in acceptor doped lead-free Ba(Ti_0.8Zr_0.2)O₃-50(Ba_0.7Ca_0.3)TiO₃ ceramic

Acceptor doping is effective in enhancing thermal stability in piezoceramics, while the reason underlying is still unclear and awaits explanation. In this work, through doping acceptor Mn in lead-free Ba(Ti_0.8Zr_0.2)O₃-50(Ba_0.7Ca_0.3)TiO₃ ceramic, our results show that doping Mn achieves higher depolarization temperature, even higher than Curie temperature (T_C) and simultaneously a better piezoelectric thermal stability. Through microscopic and macroscopic analysis, the enhancement can be explained by the clamping effect induced by acceptor doping, which is carefully demonstrated by symmetry-conforming short-range ordering tendency theory. Thus, this work reveals the mechanism for enhanced depolarization temperature and piezoelectric thermal stability due to acceptor doping and will help developing new thermal stable lead-free piezoceramics applicable in a wider temperature range.