Li Jianting, Li Junjie, Wu Hong-Hui, Zhou Ouwei, Chen Jun, Lookman Turab, Su Yanjing, Qiao Lijie, Bai Yang
Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China.
Institute for Advanced Material and Technology, University of Science and Technology Beijing, Beijing 100083, China.
ACS Appl Mater Interfaces. 2021 Aug 18;13(32):38467-38476. doi: 10.1021/acsami.1c07714. Epub 2021 Aug 3.
The ultrahigh electrostrain and piezoelectric constant () in relaxor piezoelectric PMN-30PT single crystals are closely related to the coexistence and transition of multiple phases at the morphotropic phase boundary (MPB). However, the key mechanisms underlying the stability of the phases and their transitions are yet to be fully understood. In this work, we undertake a systematic study of the influences of phase transitions on the electrostrictive and piezoelectric behaviors in ⟨001⟩-, ⟨011⟩-, and ⟨111⟩-oriented PMN-30PT single crystals. We first classify the various phase transitions within the quasi-MPB in electric field-temperature phase diagrams as either dominated by the electric field or by temperature. We find that the electrostrain reaches a maximum at each phase transition, especially in the electric-field-dominated transitions, whereas only peaks at specific phase transitions. In particular, the electrostrain in the ⟨001⟩ crystal reaches a maximum of = 0.52% at 55 °C under an external electric field with = 15 kV/cm, primarily due to a joint contribution of the electric field-dominated rhombohedral-monoclinic and monoclinic-tetragonal phase transitions at the quasi-MPB. An ultrahigh (∼2460 pC/N) only occurs at the rhombohedral-monoclinic phase transition in the ⟨001⟩ crystal and at the rhombohedral-orthorhombic transition in the ⟨011⟩ crystal ( ∼ 1500 pC/N) due to the lower energy barriers. The temperature-dominated phase transitions also contribute toward minor peaks in electrostrain and/or . This work provides a deeper and quantitative understanding of the microscopic mechanisms underlying electrostrictive and piezoelectric behaviors relevant for the design of high-performance materials.
弛豫铁电体PMN - 30PT单晶中的超高电致应变和压电常数（）与准同型相界（MPB）处多相的共存和转变密切相关。然而，这些相的稳定性及其转变背后的关键机制尚未完全理解。在这项工作中，我们对⟨001⟩、⟨011⟩和⟨111⟩取向的PMN - 30PT单晶中相变对电致伸缩和压电行为的影响进行了系统研究。我们首先在电场 - 温度相图中将准MPB内的各种相变分类为由电场主导或由温度主导。我们发现，电致应变在每个相变处达到最大值，特别是在电场主导的相变中，而仅在特定相变处出现峰值。特别是，在外部电场 = 15 kV/cm下，⟨001⟩晶体中的电致应变在55°C时达到最大值 = 0.52%，这主要归因于准MPB处电场主导的菱方 - 单斜和单斜 - 四方相变的共同作用。仅在⟨00!⟩晶体中的菱方 - 单斜相变以及⟨011⟩晶体中的菱方 - 正交相变（ ∼ 1500 pC/N）时由于较低的能垒才会出现超高（∼2460 pC/N）。温度主导的相变也对电致应变和/或的小峰值有贡献。这项工作为与高性能材料设计相关的电致伸缩和压电行为的微观机制提供了更深入的定量理解。
