Nanoscale-correlated octahedral rotations in BaZrO 3
BaZrO3 is reportedly one of few perovskites that retains an ideal cubic structure down to zero Kelvin even though its ground state as predicted by first-principles calculations has remained contentious. Here, we combine electron diffraction with total neutron scattering measured on ceramic samples at cryogenic temperatures to demonstrate that below 80 K, this compound undergoes a structural change associated with the onset of correlated out-of-phase rotations of [ZrO6] octahedra. Here, the change is manifested in the appearance of weak but relatively sharp superlattice reflections at ½hkl (h, k, l = odd), which are readily detectable by electron diffraction. Atomistic structural refinements from the total neutron scattering data confirmed that these reflections are associated with octahedral tilting. The observed rotations are consistent with the a0a0c- type and feature a coherence length of about 3 nm. The average structure of BaZrO3, as seen by Bragg diffraction, remains cubic. According to the electron diffraction data, Nb-doped BaZrO3 undergoes a similar structural transition but in this case, the tilting couldn't be recovered from the neutron scattering, suggesting that the distortions are smaller compared to those in the pure compound.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0012704
- OSTI ID:
- 1847167
- Report Number(s):
- BNL-222814-2022-JAAM
- Journal Information:
- Physical Review. B, Journal Name: Physical Review. B Journal Issue: 21 Vol. 104; ISSN 2469-9950
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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