Enhanced temperature stability of resonance frequency and electromechanical coupling in PSN-PZT piezoelectric ceramics via phase structure engineering

High-temperature piezoelectric sensors for measurement-while-drilling (MWD) applications demand materials that simultaneously possess high piezoelectric sensitivity, low dielectric loss, and exceptional thermal stability. In this work, “hard” Mn-doped 0.02 Pb(Sb 1/2 Nb 1/2 )O 3 -(0.98- x )PbZrO 3 - x PbTiO 3 (PSN-PZ- x PT) ceramics were systematically designed. While the introduction of Mn 2+ acceptor ions effectively minimizes dielectric loss through domain wall pinning, it inevitably shifts the morphotropic phase boundary (MPB). Meanwhile, for compositions near the MPB, the temperature dependence of the resonance frequency is significantly influenced by the Zr/Ti ratio. By finely tuning the Zr/Ti ratio in the vicinity of the MPB, materials exhibiting simultaneous high piezoelectric performance and excellent thermal stability were obtained. The composition with x  = 0.465, located at the MPB, exhibited an excellent combination of properties: d 33 ∼ 320 pC/N, ε r ∼971, k p ∼0.63, T C ∼354 °C, tanδ ∼0.30%, and Q m ∼452. Remarkably, this composition demonstrated superior high-temperature stability up to 200 °C, with the resonance frequency variation (Δ f r / f r25   °C ) maintained within 2.45% and electromechanical coupling fluctuation (Δ k p / k p25   °C ) within 4.62%. These results demonstrate that the optimized Mn-doped PSN-PZT ceramics are promising candidates for high-power, high-temperature applications.