The ternary solid solution Bi_1/2(Na_0.78K_0.22)_1/2TiO₃-BiMg_1/2Ti_1/2O₃ (BNKT-BMT) was investigated for high-strain actuator applications. This study of the BNKT-BMT system looked at the macroscopic properties as a function of BMT doping, temperature, and virgin vs poled states in order to gain new insights into the impact of quenched compositional disorder on non-ergodic to ergodic behavior in relaxor ferroelectrics. A gradual transition toward ergodic relaxor ferroelectric behavior was observed in the electric field induced polarization and strain of the BNKT-BMT system with an increase in concentration of BMT and an increase in temperature. BNKT-0%BMT exhibits a remarkable room temperature large-signal piezoelectric strain equivalent to an effective piezoelectric coefficient ($d_{33}^{*}$) >1000 pm/V at 5.5 kV/mm during the first virgin drive cycle due to the significant strain arising from an irreversible field induced phase transition characteristic of a non-ergodic relaxor ferroelectric. The maximum room temperature large-signal effective piezoelectric coefficient $d_{33}^{*}$ observed for reversible bipolar cycling drive conditions was 685 pm/V at 5.5 kV/mm for BNKT-4%BMT. At elevated temperatures, compositions with reduced BMT exhibited superior $d_{33}^{*}$ performance until a relative maximum $d_{33}^{*}$ was reached and strain performance subsequently declined. This is interpreted in terms of competing strain mechanisms in relaxor ferroelectrics that vary with an increase in ergodicity of the system, as governed by factors such as composition and temperature. The work has implications for industrial actuator systems, such as those in inkjet printers.

中文翻译：

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了解无铅掺杂Bi1 / 2（Na0.78K0.22）1 / 2TiO3–BiMg1 / 2Ti1 / 2O3（BNKT-BMT）压电系统中的大应变行为

三元固溶体Bi _1/2（Na _0.78 K _0.22）_1/2 TiO ₃ -BiMg _1/2 Ti _1/2 O ₃（BNKT-BMT）已针对高应变执行器应用进行了研究。BNKT-BMT系统的这项研究着眼于BMT掺杂，温度以及原始态与极化态的关系的宏观特性，以便获得新的见解，了解淬火成分失调对弛豫铁电体中非遍历到遍历行为的影响。随着BMT浓度的增加和温度的升高，在BNKT-BMT系统的电场诱导的极化和应变中观察到了向遍历松弛铁电行为的逐渐过渡。BNKT-0％BMT表现出显着的室温大信号压电应变，等效于有效压电系数（$d_{33}^{*}$）在第一个原始驱动循环中以5.5 kV / mm的速度> 1000 pm / V，这是由于非遍历松弛铁电体的不可逆场感应相变特性引起的显着应变。最大室温大信号有效压电系数$d_{33}^{*}$对于BNKT-4％BMT，在可逆双极循环驱动条件下观察到的5.5 kV / mm的速度为685 pm / V。在升高的温度下，BMT降低的组合物表现出优异的性能$d_{33}^{*}$ 性能直至达到相对最大值 $d_{33}^{*}$达到应力，应变性能随后下降。这是根据弛豫铁电体中的竞争应变机制来解释的，该竞争应变机制随系统的遍历性的增加而变化，并受诸如成分和温度等因素的控制。这项工作对工业执行器系统（如喷墨打印机中的系统）具有影响。