title: Electric-field-induced local structural phenomena in Pb-based ABO3-type relaxor ferroelectrics.
abstract: Lead-based ABO3-type relaxors and related systems have numerous applications in modern technical devices because of their remarkably high dielectric permittivity and piezoelectric/electroelastic and electro-optic coefficients. However, lead is not desired from an environmental point of view, and to switch to alternative alkali-, Ba-, or Bi-based relaxor systems, one must understand in great detail the structural mesoscopic order and coupling processes responsible for the outstanding performance and multifunctionality of the exemplar Pb-based compounds. To elucidate the type of ferroic coupling, three relaxor compounds PbSc0.5Ta0.5O3 (PST), Pb0.78Ba0.22Sc0.5Ta0.5O3 (PST-Ba), and PbSc0.5Nb0.5O3 (PSN), were studied by polarized Raman scattering and acoustic emission at different temperatures and under an external electric field. The results reveal the coexistence of mesoscopic-scale ferroelectric and antiferroelectric coupling, which are predominantly related to B-site cations and A-site Pb cations, respectively. This suggests that the polar structural state of relaxors is frustrated ferrielectric. The presence of A-site cations with affinity to off-center is significant for the development of mesoscopic-scale antiferroelectric order coexisting with the mesoscopic-scale ferroelectric order.
authors.forename: Boriana
authors.initials: B
authors.lastname: Mihailova
authors.forename: Bernd J
authors.initials: BJ
authors.lastname: Maier
authors.forename: Thomas
authors.initials: T
authors.lastname: Steilmann
authors.forename: Evgeniy
authors.initials: E
authors.lastname: Dul'kin
authors.forename: Michael
authors.initials: M
authors.lastname: Roth