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Structural distortions such as cation off-centering are frustrated in the pyrochlore structure due to the triangular arrangement of cations on the pyrochlore lattice. This geometric constraint inhibits a transition from a paraelectric to ferroelectric phase in majority of pyrochlore oxide materials. Few pyrochlore materials can overcome this frustration and exhibit polar crystal structures, and unraveling the origin of such leads to the understanding of polarity in complex materials. Herein we hypothesize that frustration on the pyrochlore lattice can be relieved through A -site doping with rare earth cations that do not possess stereochemically active lone pairs. To assess if frustration is relieved, we have analyzed cation off-centering in various Bi 2−x RE xTi 2 O 7 ( RE = Y 3+ , Ho 3+ ) pyrochlores through neutron and X-ray total scattering. Motivated by known distortions from the pyrochlore literature, we present our findings that most samples show local distortions similar to the β-cristobalite structure. We additionally comment on the complexity of factors that play a role in the structural behavior, including cation size, bond valence, electronic structure, and magnetoelectronic interactions. We posit that the addition of magnetic cations on the pyrochlore lattice may play a role in an extension of the real-space correlation length of electric dipoles in the Bi-Ho series, and offer considerations for driving long-range polarity on the pyrochlore lattice.
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This content will become publicly available on December 12, 2025
Combinatorial synthesis and characterization of thin film Al 1−x RE x N (RE = Pr 3+ and Tb 3+ ) heterostructural alloys
High-throughput combinatorial synthesis of Al1−xRExN (RE = Pr, Tb) thin films with 0 <x< 0.4 was performed to assess composition-phase-property relationships in an emerging materials family.
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- Award ID(s):
- 2119281
- PAR ID:
- 10560212
- Publisher / Repository:
- Royal Society of Chemistry
- Date Published:
- Journal Name:
- Journal of Materials Chemistry C
- Volume:
- 12
- Issue:
- 48
- ISSN:
- 2050-7526
- Page Range / eLocation ID:
- 19620 to 19630
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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