Perovskite BY GM12 Oxides with a perovskite structure yield many commercial ferroelectrics (materials that possess a net macroscopic polarization switchable under external electric field). The structure of these oxides, having a general formula AB03, can be represented as a network of corner-sharing oxygen octahedra with higher-charge cations B located inside these octahedra and lower-charge cations A occupying the cavities between the octahedra. Typically the spontaneous polarization originates from the concerted ff-centering of cations B, which generates an electric dipole.
This polarizing behavior occurs in a classical ferroelectric material BaTi03. However, some perovskite materials, such as PbTi03 exhibit off-centering of both A (Pb) and B (T’) cations, which then results in even larger values of electric polarization. The theoretical calculations performed in this paper demonstrate that a ferroelectric behavior in BaTi03 and PbTi03 results from hybridization between the electrons on the titanium and oxygen atoms, which overcomes the repulsive interatomic forces nd stabilizes large off-centering of T’.
In PbTi03, the effect is enhanced by the additional Pb-O hybridization. Reference: R. E. Cohen, “Origin of Ferroelectricity in Perovskite Oxide,” Nature, 358, 136 (1992) Ins10e tnese octaneara ana lower-cnarge catlons A occupylng tne cavltles Detween Denavlor In Bal 103 ana PD 1103 resul ts Trom nyDr101zatlon Detween tne electrons on and stabilizes large off-centering of Ti. In PbTi03, the effect is enhanced by the I ne structure 0T tnese ox10es, navlng a general Tormula AB03, can De represented as
