Terahertz and infrared studies of antiferroelectric phase transition in multiferroic Bi.sub.0.85./sub.Nd.sub.0.15./sub.FeO.sub.3./sub..

0367281 - FZÚ 2012 RIV US eng J - Journal Article
Goian, Veronica - Kamba, Stanislav - Greicius, S. - Nuzhnyy, Dmitry - Karimi, S. - Reaney, I. M.
Terahertz and infrared studies of antiferroelectric phase transition in multiferroic Bi_0.85Nd_0.15FeO₃.
Journal of Applied Physics. Roč. 110, č. 7 (2011), 074112/1-074112/5. ISSN 0021-8979. E-ISSN 1089-7550
R&D Projects: GA ČR GD202/09/H041; GA ČR(CZ) GA202/09/0682
Grant - others:GA UK(CZ) SVV-2011-263303
Institutional research plan: CEZ:AV0Z10100520
Keywords : multiferroics * infrared and THz spectroscopy * phonons * antiferroelectrics
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 2.168, year: 2011

High-frequency dielectric studies of Bi0.85Nd0.15FeO3 ceramics performed betweeen 100 and 900 K reveal hardening of most polar phonons on cooling below antiferroelectric phase transition, which occurs near 600 K. Moreover, a strong THz dielectric relaxation is seen in paraelectric phase. Its relaxation frequency softens on cooling towards TC = 600 K, its dielectric strength simultaneously decreases, and finally the relaxation disappears from the spectra below 450 K. Both phonon and dielectric relaxation behavior are responsible for a decrease in the dielectric permittivity at the antiferroelectric phase transition. Origin of unusual strong THz dielectric relaxation in paraelectric phase is discussed.
Permanent Link: http://hdl.handle.net/11104/0202021