Perovskite ferroelectrics possess the fascinating piezoelectric properties near a morphotropic phase boundary, attributing to a low energy barrier that the results in structural instability and easy polarization rotation. In this work, a new lead-free system of (1-x)BaTiO₃-xCaHfO₃ was designed, and characterized by a coexistence of ferroelectric rhombohedral-orthorhombic-tetragonal (R-O-T) phases. With the increase amount of CaHfO₃ (x), a stable coexistence region of three ferroelectric phases (R-O-T) exists at 0.06 ≤ x ≤ 0.08. Both large piezoelectric coefficient (d₃₃∼400 pC/N), inverse piezoelectric coefficient (d₃₃^*∼547 pm/V) and planar electromechanical coupling factor (k_p∼58.2%) can be achieved for the composition with x = 0.08 near the coexistence of three ferroelectric phases. Our results show that the materials with the composition located at a region where the three ferroelectric R-O-T phases coexist would have the lowest energy barrier and thus greatly promote the polarization rotation, resulting in a strong piezoelectric response.

钙钛矿铁电体在趋晶相边界附近具有引人入胜的压电特性，这归因于低能垒，导致结构不稳定和易于极化旋转。在这项工作中，设计了一种新的（1- x）BaTiO ₃ - x CaHfO ₃无铅体系，并以铁电菱形-斜方-斜方-四方（ROT）相共存为特征。与CaHfO的增加量₃（X），三个铁电相的稳定共存区域（ROT）存在于0.06≤  X  ≤0.08。两者的压电系数均大（d ₃₃〜400 PC / N），逆压电系数（d ₃₃ ^* ~547 PM / V）和平面机电耦合因子（ķ _p可以用于与组合物来实现~58.2％）X  = 0.08的3个强电介质相的共存的附近。我们的结果表明，组成位于三个铁电ROT相共存的区域的材料将具有最低的能垒，从而极大地促进了极化旋转，从而产生了强大的压电响应。