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Updated: Jun 17, 2025
06:24
High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal
Published on: October 31, 2019
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The high-pressure structure of (1-x)Na Bi TiO -xBaTiO at the morphotropic phase boundary.
Constanze Rösche1, Tiziana Boffa Ballaran2, Thomas Malcherek3
1Department of Earth System Sciences, Universität Hamburg, Grindelallee 48, 20146, Hamburg, Germany. constanze.roesche@uni-hamburg.de.
Scientific Reports
|August 13, 2024
Summary
Pressure transforms (1-x)NaBiTiO3-xBaTiO3 ferroelectrics at the morphotropic phase boundary. A new orthorhombic phase emerges above 4.4 GPa, featuring BO6 tilts and anti-polar cation displacements.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Crystallography
Background:
- Ferroelectric solid solutions like (1-x)NaBiTiO3-xBaTiO3 (NBT-xBT) exhibit complex phase behavior near the morphotropic phase boundary (MPB).
- Understanding pressure-induced structural transformations is crucial for tailoring their functional properties.
Purpose of the Study:
- To investigate the pressure-dependent structural evolution of NBT-xBT at the MPB.
- To identify phase transitions and characterize the high-pressure crystal structure.
Main Methods:
- Single-crystal X-ray diffraction using synchrotron radiation.
- Analysis of structural changes up to 12.3 GPa.
Main Results:
- A pressure-induced phase transition occurs between 4.4 and 5.0 GPa, from a pseudocubic to an orthorhombic (Pnma) phase.
- The high-pressure orthorhombic phase exhibits mixed BO6 tilts and anti-polar A-cation displacements.
- At ambient conditions, NBT-xBT shows anti-phase BO6 tilts and polar distortions, with Ba-induced stress affecting correlation length.
Conclusions:
- External pressure can restore structural features similar to pure NBT in Ba-substituted compositions.
- The study elucidates the intricate interplay between composition, pressure, and structure in NBT-xBT ferroelectrics.
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