Yan Yongke, Geng Liwei D, Liu Hairui, Leng Haoyang, Li Xiaotian, Wang Yu U, Priya Shashank
Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA, 16802, USA.
Department of Materials Science and Engineering, Michigan Technological University, Houghton, MI, 49931, USA.
Nat Commun. 2022 Jun 22;13(1):3565. doi: 10.1038/s41467-022-31165-y.
Electromechanical coupling factor, k, of piezoelectric materials determines the conversion efficiency of mechanical to electrical energy or electrical to mechanical energy. Here, we provide an fundamental approach to design piezoelectric materials that provide near-ideal magnitude of k, via exploiting the electrocrystalline anisotropy through fabrication of grain-oriented or textured ceramics. Coupled phase field simulation and experimental investigation on <001> textured Pb(MgNb)O-Pb(Zr,Ti)O ceramics illustrate that k can reach same magnitude as that for a single crystal, far beyond the average value of traditional ceramics. To provide atomistic-scale understanding of our approach, we employ a theoretical model to determine the physical origin of k in perovskite ferroelectrics and find that strong covalent bonding between B-site cation and oxygen via d-p hybridization contributes most towards the magnitude of k. This demonstration of near-ideal k value in textured ceramics will have tremendous impact on design of ultra-wide bandwidth, high efficiency, high power density, and high stability piezoelectric devices.
压电材料的机电耦合系数k决定了机械能到电能或电能到机械能的转换效率。在此，我们提供了一种基本方法来设计具有接近理想k值的压电材料，即通过制造取向或织构化陶瓷来利用电晶体各向异性。对<001>织构化的Pb(MgNb)O-Pb(Zr,Ti)O陶瓷进行的耦合相场模拟和实验研究表明，k可以达到与单晶相同的量级，远远超过传统陶瓷的平均值。为了从原子尺度理解我们的方法，我们采用理论模型来确定钙钛矿铁电体中k的物理起源，并发现B位阳离子与氧之间通过d-p杂化形成的强共价键对k的量级贡献最大。织构化陶瓷中接近理想k值的这一证明将对超宽带宽、高效率、高功率密度和高稳定性压电器件的设计产生巨大影响。
