Thermal stability of the electromechanical properties in acceptor-doped and composite-hardened (Na_1/2Bi_1/2)TiO₃–BaTiO₃ ferroelectrics

Lead-free relaxor ferroelectrics are promising candidates for next-generation piezoelectric high-power devices, such as ultrasonic motors, transformers, and therapeutic ultrasonics. These applications require hard with a broad operating temperature range. Recently, acceptor Zn2+ doping composite formation ZnO were proposed to induce hardening in Na1/2Bi1/2TiO3–BaTiO3 simultaneously increase the depolarization temperature. Here, these two strategies compared by studying dependence of electromechanical properties, ferroelectric loops, nonlinear polarization harmonics. In modified compositions, is associated shift ferroelectric-to-relaxor transition higher temperatures, while onset remains unchanged. This leads broadening rather than translation region, accompanied decoupling d33 d31 coefficients. The temperature-dependent response stable composites, Zn2+-doped samples exhibit strong akin acceptor-doped Pb(Zr,Ti)O3. thermal evolution coefficients not related thermally induced decrease coercive/internal bias fields but instead ratio irreversible-to-reversible dynamics arising from displacements domain walls or similar interfaces. results demonstrate that mechanical stress-based composites exhibits superior stability, which can considerably improve operational range lead-free materials.