Reference : Unraveling the suppression of oxygen rotations motions from ABO3 to A3B2O7 perovskite...
Scientific congresses and symposiums : Unpublished conference/Abstract
Physical, chemical, mathematical & earth Sciences : Physics
http://hdl.handle.net/2268/247659
Unraveling the suppression of oxygen rotations motions from ABO3 to A3B2O7 perovskites : new perspectives for room-temperature multiferroics
English
Zhang, Yajun mailto [Université de Liège - ULiège > Département de physique > Physique théorique des matériaux >]
jie, Wang mailto [Zhejiang University > Department of Engineering Mechanics > > >]
Ghosez, Philippe mailto [Université de Liège - ULiège > Département de physique > Physique théorique des matériaux >]
16-Jul-2019
No
2019 IEEE International Symposium on Applications of Ferroelectrics (ISAF)
from 14-07-2019 to 19-07-2019
[en] ferroelectricity ; rotations ; perovskites
[en] Ruddlesden¿Popper (RP) A3B2O7 hold great promise for realizing strong magneto-electric multiferroics due to the trilinear coupling [1] of polar distortions with oxygen rotation motions, which are further controlling weak ferromagnetism [2,3]. Unfortunately, for a majority of Pnma ABO3 perovskites, the desired a¿a¿c+ rotation pattern combining in-phase and out-of-phase rotations, required for producing hybrid improper ferroelectricity, is reduced to a-b0c0/b-a0c0 when forming A3B2O7 structure, which makes experimental realization of multiferroic A3B2O7 RP compounds exceedingly rare [4]. The microscopic mechanism at the origin of such a suppression of oxygen rotation motions is still unclear. Here, taking recently synthesized Tb2SrFe2O7 [4] as an prototypical example, we combine first-principles calculations and Landau-type theory to highlight a strong competition between oxygen rotations and interfacial rumpling at the AO rocksalt layer interface, which is present in A3B2O7 structures and absent in ABO3 simple perovskites. This competition suppresses rotations and prevents the appearance of improper ferroelectricity. Distinct practical approaches [5] are then proposed to avoid such rumpling or enhance oxygen rotations, aiming at recovering the a¿a¿c+ rotation pattern and realizing room-temperature multiferroics. The proposed approaches are generic and also applicable to other perovskites like manganites, chromates and nickelates, which opens the door to the design of a wide variety of multiferroics.
Researchers ; Professionals ; Students
http://hdl.handle.net/2268/247659

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