A combinatory ferroelectric compound bridging simple ABO<sub>3</sub> and A-site-ordered quadruple perovskite.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 33531480.
- Also identified by DOI 10.1038/s41467-020-20833-6 and PMC identifier 7854592.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The simple ABO<sub>3</sub> and A-site-ordered AA'<sub>3</sub>B<sub>4</sub>O<sub>12</sub> perovskites represent two types of classical perovskite functional materials. There are well-known simple perovskites with ferroelectric properties, while there is still no report of ferroelectricity due to symmetry breaking transition in A-site-ordered quadruple perovskites. Here we report the high pressure synthesis of an A-site-ordered perovskite PbHg<sub>3</sub>Ti<sub>4</sub>O<sub>12</sub>, the only known quadruple perovskite that transforms from high-temperature centrosymmetric paraelectric phase to low-temperature non-centrosymmetric ferroelectric phase. The coordination chemistry of Hg<sup>2+</sup> is changed from square planar as in typical A-site-ordered quadruple perovskite to a rare stereo type with 8 ligands in PbHg<sub>3</sub>Ti<sub>4</sub>O<sub>12</sub>. Thus PbHg<sub>3</sub>Ti<sub>4</sub>O<sub>12</sub> appears to be a combinatory link from simple ABO<sub>3</sub> perovskites to A-site-ordered AA'<sub>3</sub>Ti<sub>4</sub>O<sub>12</sub> perovskites, sharing both displacive ferroelectricity with former and structure coordination with latter. This is the only example so far showing ferroelectricity due to symmetry breaking phase transition in AA'<sub>3</sub>B<sub>4</sub>O<sub>12</sub>-type A-site-ordered perovskites, and opens a direction to search for ferroelectric materials.