An international team of researchers is paving the path to discovering and developing new materials capable of flipping their electrical polarization — a critical property for components in sensors, memory storage devices and more.
Led by Changqing Jin, professor in the Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences (IOPCAS), scientists fabricated a structural bridge to induce the electrical polarization switch in more sophisticated, and potentially more plentiful materials.
The research team presented their findings at the 2021 Fall Meeting of the European Materials Research Society (E-MRS)(https://www.european-mrs.com/emergent-functional-materials-respect-extreme-conditions-emrs-0) held between September 20 and 23. The paper was originally published earlier this year in Nature Communications 12:747(2021).
The research team focused on the crystal structure of perovskite, named for a mineral. Simple perovskites are widely available, with an atomic structure that can lead to electrical polarization, also called displacive ferroelectricty.
“Ferroelectricity is one of most important properties of perovskite compounds with wide applications in electronic industry,” said paper co-author Yunze Yu, professor in Beijing University of Science & Technology...
Another, more complicated perovskite is called high-order perovskite. Its structure consists of multiple simple perovskites, but they do not behave as the simple version does when combined in the larger structure. As a result, their individual properties, such as displacive ferroelectricity, do not translate to the high-order perovskite.
“Finding a bridge between simple perovskite and a high-order perovskite, such as the A-site-ordered perovskite, in structure is a challenge in material design and synthesis,” Jin said. “With the advancement of high-pressure synthesis technology, high-order perovskites with several simple perovskite units in a large single unit cell becomes possible.”
According to Yu, however, there has not previously been a convincing experimental report of displacive-type ferroelectricity — the electrical polarization change — in high-order perovskite compounds.
To build up the desired structure of A-site-ordered perovskites, the researchers applied more than 60,000 times the atmospheric pressure to synthesize a new material composed of oxides of lead, mercury, titanium at about 1,830 degrees Fahrenheit for 30 minutes. The new material, dubbed PHTO, has the right chemical composition and structure type to bridge simple perovskite and A-site ordered perovskite.
“PHTO appears to be a combinatory link from simple perovskites to A-site-ordered perovskites, sharing both displacive ferroelectricity with the former and structural coordination with the latter,” said first author Jianfa Zhao, a post doc at Songshan Lake Material Lab.
The new material ties the two types of perovskites together in a structure that is more ideally arranged, but with electrical polarized physical property capabilities that can occur near-room temperature needed for developing next-generation devices and technologies.
According to Zhao, this result is key because it could allow researchers to induce electrical polarization changes in even more new materials by the same strategy, which could have other useful properties.
“This work opens a new direction to search for near-room temperature ferroelectric materials,” Zhao said. “Advanced high-pressure synthesis technology is promising to broaden the scope of forefront of condensed matters via building up new structures with unusual properties.”
According to Yu, however, there has not previously been a convincing experimental report of displacive-type ferroelectricity — the electrical polarization change — in high-order perovskite compounds.
To build up the desired structure of A-site-ordered perovskites, the researchers applied more than 60,000 times the atmospheric pressure to synthesize a new material composed of oxides of lead, mercury, titanium at about 1,830 degrees Fahrenheit for 30 minutes. The new material, dubbed PHTO, has the right chemical composition and structure type to bridge simple perovskite and A-site ordered perovskite.
“PHTO appears to be a combinatory link from simple perovskites to A-site-ordered perovskites, sharing both displacive ferroelectricity with the former and structural coordination with the latter,” said first author Jianfa Zhao, a post doc at Songshan Lake Material Lab.
The new material ties the two types of perovskites together in a structure that is more ideally arranged, but with electrical polarized physical property capabilities that can occur near-room temperature needed for developing next-generation devices and technologies.
According to Zhao, this result is key because it could allow researchers to induce electrical polarization changes in even more new materials by the same strategy, which could have other useful properties.
“This work opens a new direction to search for near-room temperature ferroelectric materials,” Zhao said. “Advanced high-pressure synthesis technology is promising to broaden the scope of forefront of condensed matters via building up new structures with unusual properties.”