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Crystallographic and optical study of PbHfO3 crystals
S Huband1, A M Glazer2, K Roleder3
1Department of Physics, University of Warwick , Coventry, West Midlands CV4 7AL, UK.
Journal of Applied Crystallography
|April 7, 2017
Summary
The symmetry of lead hafnate (PbHfO3) at high temperatures was confirmed as orthorhombic. This finding, crucial for understanding ferroelectric materials, was determined using advanced X-ray diffraction and microscopy techniques.
Area of Science:
- Solid State Physics
- Materials Science
- Crystallography
Background:
- Lead hafnate (PbHfO3) is a material with potential applications in ferroelectric devices.
- Understanding its phase transitions and crystal symmetry is crucial for optimizing its properties.
- Previous studies suggested possible orthorhombic or tetragonal symmetry for its intermediate high-temperature phase.
Purpose of the Study:
- To unambiguously determine the crystal symmetry of the intermediate high-temperature phase of PbHfO3.
- To resolve discrepancies in previous symmetry assignments.
- To provide a definitive structural understanding for future material applications.
Main Methods:
- High-resolution X-ray diffraction (HRXRD) was employed to analyze lattice parameters as a function of temperature.
- Birefringence imaging microscopy, specifically using the Metripol system, was utilized to observe domain orientations.
- Data from both techniques were combined for a comprehensive structural analysis.
Main Results:
- Lattice parameter measurements were consistent with both orthorhombic and tetragonal symmetries.
- Birefringence imaging microscopy revealed domain orientations exclusively matching orthorhombic symmetry.
- The unit cell was identified in the rhombic orientation within the pseudocubic unit cell.
Conclusions:
- The intermediate high-temperature phase of PbHfO3 is unambiguously orthorhombic.
- Birefringence imaging microscopy is a powerful tool for resolving crystallographic ambiguities.
- This definitive symmetry determination aids in the understanding and application of PbHfO3 in electronic devices.
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