Ultrahigh temperature stability in heterovalent-ion doped PZT ceramics

We achieved ultrahigh temperature stability of the piezoelectric coefficient d₃₃ by doping heterovalent ions in the PbZr_0.54Ti_0.46O₃ ceramics at the A/B sites in the ABO₃ lattice. The Sm³⁺-ion amount at the A-site remains constant, while the Ta⁵⁺-ion amount at the B-site changes. We utilized electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS) to investigate the reduction of oxygen vacancies, which are closely associated with the defect dipoles formed by heterovalent doping. We utilized piezoresponse force microscopy (PFM), temperature-dependent X-ray diffraction (XRD) combined with Rietveld refinement, and temperature-dependent Raman spectroscopy to understand the mechanism of the temperature stability of the piezoelectric coefficient d₃₃. When x=0.01, the performance of xTa-0.01Sm-PbZr_0.54Ti_0.46O₃ ceramic is optimal: d₃₃=530 pC/N, electromechanical coupling factor k_p=0.72, Curie temperature T_C =343 °C, where the temperature stability of the piezoelectric coefficient is ultrahigh, and the d₃₃ changes only 2.2% over the 25−200 °C temperature range.