Sotf mode in cubic PbTiO3 by hyper-Raman scattering

J. Hlinka (1) , Bernard Hehlen (2) , A. Kania (3) , I. Gregora (1)

1 Institute of Physics [Prague]
2 L2C - Laboratoire Charles Coulomb
3 Institut of Physics, University of Silesia

Hyper-Raman scattering experiments allowed collecting the spectra of the lowest F1u-symmetry mode of PbTiO3 crystal in the paraelectric phase up to ≈930 K as well as down to about 1 K above the phase transition. It is realized that this mode is fully responsible for the Curie-Weiss behavior of its dielectric permittivity above Tc. Near the phase transition, this phonon frequency softens down to 17 cm-1 and its spectrum can be well modeled as a response of a single damped harmonic oscillator. It is concluded that PbTiO3 constitutes a clean example of a soft-mode-driven ferroelectric system.

Mots clés: PbTiO3; Ferroelectric; soft mode; hyper-Raman

Domaines: Systèmes désordonnés et réseaux de neurones [cond-mat.dis-nn]

J. Hlinka, Bernard Hehlen, A. Kania, I. Gregora. Sotf mode in cubic PbTiO3 by hyper-Raman scattering. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2013, 87, pp.064101. ⟨10.1103/PhysRevB.87.064101⟩. ⟨hal-00797857⟩