Gozuacik Namik Kemal, Bayir Mustafa Cagri, Mensur-Alkoy Ebru, Alkoy Sedat
IEEE Trans Ultrason Ferroelectr Freq Control. 2021 Jul;68(7):2576-2584. doi: 10.1109/TUFFC.2021.3063146. Epub 2021 Jun 29.
In this study, effects of rare-earth elements such as Nd, Gd, and Ce on the structural and electrical properties of lead-free bismuth sodium potassium barium titanate BiNaKBaTiO (0.854BNT-0.12BKT-0.026BT) (BNKBT) ceramics have been investigated in detail. Solid-state reaction method was used to prepare undoped, 1.0 mol% Nd, 1.0 mol% Gd, 1.0 mol%, 2.1 mol%, and 2.7 mol% Ce-doped BNKBT ceramic powder compositions. A pure single perovskite structure was observed in the X-ray diffraction (XRD) patterns for all the BNKBT ceramic systems, although doping was found to cause changes in peak splitting and peak positions due to their site preference. The Curie temperatures have not shifted significantly with doping, but the relative permittivity values were found to have increased. The nonergodic normal ferroelectric character of undoped BNKBT ceramic switched to an ergodic relaxor character at room temperature with Nd, Gd, and Ce doping with pinched polarization vs electric field hysteresis loops. Increased field-induced strain levels were observed in the doped BNKBT ceramics with 1 mole% Ce doping yielding a giant field-induced strain of 0.38% under an E -field of 65 kV/cm. Nd-doping, on the other hand, resulted in the highest releasable energy density of 0.64 J/cm at 65 kV/cm. Consequently, the rare-earth-doped BNKBT ceramics were found to be promising for both digital actuator and high-energy-density capacitor applications due to their favorable electrical properties.
在本研究中，详细研究了钕（Nd）、钆（Gd）和铈（Ce）等稀土元素对无铅铋钠钾钡钛酸盐BiNaKBaTiO（0.854BNT - 0.12BKT - 0.026BT）（BNKBT）陶瓷的结构和电学性能的影响。采用固态反应法制备了未掺杂、1.0摩尔% Nd、1.0摩尔% Gd、1.0摩尔%、2.1摩尔%和2.7摩尔% Ce掺杂的BNKBT陶瓷粉末组合物。在所有BNKBT陶瓷体系的X射线衍射（XRD）图谱中均观察到纯单相钙钛矿结构，尽管由于掺杂元素的占位偏好，发现掺杂会导致峰分裂和峰位置发生变化。居里温度随掺杂没有明显偏移，但相对介电常数有所增加。未掺杂的BNKBT陶瓷的非遍历正常铁电特性在室温下随着Nd、Gd和Ce掺杂转变为遍历弛豫特性，极化与电场滞后回线变窄。在掺杂的BNKBT陶瓷中观察到场致应变水平增加，1摩尔% Ce掺杂在65 kV/cm的电场下产生了0.38%的巨大场致应变。另一方面，Nd掺杂在65 kV/cm时导致了最高的可释放能量密度0.64 J/cm。因此，由于其良好的电学性能，稀土掺杂的BNKBT陶瓷被认为在数字致动器和高能量密度电容器应用方面都很有前景。
