Symmetry-mode analysis for intuitive observation of structure-property relationships in the lead-free antiferroelectric (1-x)AgNbO3-xLiTaO3
[2];
[1];
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[3];
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- Australian National Univ., Canberra, ACT (Australia)
- Xi’an Jiaotong Univ., Xi’an, Shannxi (China); Australian National Univ., Canberra, ACT (Australia); Queen Mary Univ. of London, London (United Kingdom)
- Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)
- Australian National Univ., Canberra, ACT (Australia); Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)
Functional materials are of critical importance to electronic and smart devices. A deep understanding of the structure–property relationship is essential for designing new materials. In this work, instead of utilizing conventional atomic coordinates, a symmetry-mode approach is successfully used to conduct structure refinement of the neutron powder diffraction data of (1-x)AgNbO3–xLiTaO3 (0 ≤ x ≤ 0.09) ceramics. This provides rich structural information that not only clarifies the controversial symmetry assigned to pure AgNbO3 but also explains well the detailed structural evolution of (1-x)AgNbO3–xLiTaO3 (0 ≤ x ≤ 0.09) ceramics, and builds a comprehensive and straightforward relationship between structural distortion and electrical properties. It is concluded that there are four relatively large-amplitude major modes that dominate the distorted Pmc21 structure of pure AgNbO3, namely a Λ3 antiferroelectric mode, a T4+ a-a-c0 octahedral tilting mode, an H2 a0a0c+/a0a0c- octahedral tilting mode and a Γ4- ferroelectric mode. The H2 and Λ3 modes become progressively inactive with increasing x and their destabilization is the driving force behind the composition-driven phase transition between the Pmc21 and R3c phases. This structural variation is consistent with the trend observed in the measured temperature-dependent dielectric properties and polarization–electric field (P-E) hysteresis loops. The mode crystallography applied in this study provides a strategy for optimizing related properties by tuning the amplitudes of the corresponding modes in these novel AgNbO3-based (anti)ferroelectric materials.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- Australian Research Council (ARC); International Science and Technology Cooperation Program of China; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
- Grant/Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1571467
- Journal Information:
- IUCrJ, Journal Name: IUCrJ Journal Issue: 4 Vol. 6; ISSN 2052-2525; ISSN IUCRAJ
- Publisher:
- International Union of CrystallographyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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