当前位置: X-MOL 学术J. Materiomics › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Structural and microstructural description of relaxor-ferroelectric transition in quenched Na1/2Bi1/2TiO3BaTiO3
Journal of Materiomics ( IF 9.4 ) Pub Date : 2022-01-27 , DOI: 10.1016/j.jmat.2022.01.006
Andreas Wohninsland 1 , Ann-Katrin Fetzer 1 , Rachel Broughton 2 , Jacob L. Jones 2 , K.V. Lalitha 1
Affiliation  

Quenching lead-free Na1/2Bi1/2TiO3-based ceramics from sintering temperature is established to increase the depolarization temperature, Td and the lattice distortion. In situ synchrotron X-ray diffraction measurements were carried out on furnace cooled and quenched Na1/2Bi1/2TiO3 - BaTiO3 (NBT-BT) with 6 and 9 mol. % BT to discern the field-induced ferroelectric order. Phase fractions were determined from full pattern Rietveld refinements and utilized together with the change in unit cell volume to calculate volumetric strain resulting from phase transformations. NBT-6BT demonstrates a cubic symmetry in the furnace cooled state but quenching stabilizes the rhombohedral R3c phase and delays the formation of a field-induced, long range-ordered tetragonal phase, thereby shifting the onset of macroscopic strain to higher fields. A field-induced phase transition from a weakly distorted rhombohedral to tetragonal phase can be observed in furnace cooled NBT-9BT. However, this phase transition cannot be detected in quenched NBT-9BT, since the ferroelectric tetragonal P4mm phase is stabilized in the initial state. In contrast to the furnace cooled materials, both the quenched compositions exhibit overall negligible volumetric strain as a function of electric field. Furthermore, scanning electron micrographs of chemically etched, poled and unpoled samples reveal an increased lamellar domain contrast in the quenched materials. All these findings strengthen the hypothesis of a stabilized ferroelectric order resulting in the absence of a field-induced phase transformation in quenched NBT-BT.



中文翻译:

淬火 Na1/2Bi1/2TiO3BaTiO3 中弛豫-铁电转变的结构和微观结构描述

建立从烧结温度淬火无铅Na 1/2 Bi 1/2 TiO 3基陶瓷以提高去极化温度、T d和晶格畸变。原位同步加速器X射线衍射测量在炉冷却和淬火的Na 1/2 Bi 1/2 TiO 3  - BaTiO 3上进行(NBT-BT) 与 6 和 9 mol。% BT 来辨别场感应的铁电顺序。相分数由完整模式的 Rietveld 改进确定,并与晶胞体积的变化一起用于计算相变产生的体积应变。NBT-6BT 在炉冷状态下表现出立方对称性,但淬火稳定了菱面体R 3 c相并延迟了场诱导的长程有序四方相的形成,从而将宏观应变的开始转移到更高的场。在炉冷的 NBT-9BT 中可以观察到场诱导的从弱扭曲的菱面体相到四方相的相变。然而,在淬火的 NBT-9BT 中无法检测到这种相变,因为铁电四方P 4 mm相稳定在初始状态。与炉冷材料相比,两种淬火组合物都表现出作为电场函数的整体可忽略不计的体积应变。此外,化学蚀刻、极化和非极化样品的扫描电子显微照片揭示了淬火材料中增加的层状域对比度。所有这些发现都加强了稳定铁电顺序的假设,导致淬火的 NBT-BT 中不存在场诱导的相变。

更新日期:2022-01-27
down
wechat
bug