Evidence for competing orderings in strontium titanate from hyper-Raman scattering spectroscopy

Abstract

The frequencies of the softest polar optic phonons of tetragonal SrTiO3 are accurately determined using high-resolution hyper-Raman spectroscopy on oriented-domain crystals. The splitting of the polar soft mode in the tetragonal phase is quantitatively related to the 105 K structural transition, i.e., to the rotation of the oxygen octahedra and to the associated macroscopic strains. In addition to quantum fluctuations, these tetragonal distortions are found to be essential in preventing the ferroelectric transition.

Optical study of the vibrational and dielectric properties ofBiMnO3

“…3 is their temperature dependence. The frequencies do not change appreciably with T , and no phonon softening is observed which may indicate displacive ferroelectricitynot even incipient as in SrTiO 3 [30]. Moreover, we do not observe any appreciable shift in the ω j 's around or below the FM transition.…”

Quantum Paraelectric States in SrTiO3and KTaO3: Barrett Model, Vendik Model, and Quantum Criticality

“…14) In addition, a value of about 40,000 has been estimated using hyper-Raman scattering measurements. 14,15) Our (100) plate sample with a maximum value of 36,000 was estimated to be a monodomain crystal, which required the introduction of a secondary order parameter, associated with the structural Prior to the analyses using quantum mechanical formulae, the temperature dependence of ε ′ measured at 10 kHz above 150 K was analyzed using the classical Curie-Weiss formula, Table II.…”

Influence of SrTiO3 Buffer Layer on the Ferroelectric Properties of Bi2NiMnO6 Thin Film

“…In order to enhance the polarization, a buffer layer such as SrTiO 3 has been taken into account. A lot of work devoting to calculation of lattice dynamics of perovskite thin film of SrTiO 3 indicated that ferroelectric instability arising in thin film of SrTiO 3 on the substrate [8,9]. Sadovskaya et el.…”