Beyond MPB engineering: enhanced piezoelectricity and thermal stability assisted by high-entropy design
Al Momin Md Tanveer Karim1,2, Ying Liu3, John Daniels4
1Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, Wollongong, NSW, Australia.
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The pursuit of ferroelectric materials that combine a high piezoelectric response with robust thermal stability remains a paramount challenge. We introduce a strategy that integrates morphotropic phase boundary (MPB) engineering with high-entropy (HE) design in a novel quinary Pb(Yb1/2Nb1/2)O3-Pb(Zn1/3Nb2/3)O3-Pb(Fe1/2Nb1/2)O3-PbZrO3-PbTiO3 (PYN-PZN-PFN-PZ-PT) perovskite ceramic. Compared to a medium-entropy counterpart, the high-entropy composition yields a superior piezoelectric coefficient of 580 pC/N and exceptional thermal stability, with performance retained up to 285 °C. This enhancement arises from two synergistic effects of the HE design: a stabilized, flattened free-energy landscape that promotes a favorable nanoscale domain structure and improves depolarization behavior, together with higher electrical resistivity (109 Ω·cm at 250 °C) arising from HE-driven grain refinement and suppressed charge transport. This work demonstrates that HE design serves as an effective strategy to mitigate the traditional trade-off between piezoelectric response and depolarization temperature in Pb-based relaxor ferroelectrics.
