Pressure-dependent Raman scattering of polycrystalline KNb 1-x Ta x O 3 solid solutions

E. Di Geronimo , Veronique Bornand (1) , Ph. Baranek , Ph. Papet (1)

1 ICGM - Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier

We report experimental and calculated Raman scattering investigations of KNb 1-x Ta x O 3 (x = 0.4, 0.5, 0.6) solid solutions as a function of hydrostatic pressure. The observed phase transitions sequence in the range from room pressure to 12 GPa is similar to the temperature-induced structural phase transformations: orthorhombic (ferroelectric) to tetragonal (ferroelectric) to cubic (paraelectric). Furthermore, it was observed that the domain of stability of ferroelectricity at high pressures increases with Nb-content. For the first time, some DFT calculations of theoretical Raman spectra are reported in order to support the experimental observations of pressure-induced phase transitions.

Mots clés: high pressure Raman spectroscopy; phase transitions; potassium niobate tantalite; DFT

Domaines: Science des matériaux [cond-mat.mtrl-sci]

E. Di Geronimo, Veronique Bornand, Ph. Baranek, Ph. Papet. Pressure-dependent Raman scattering of polycrystalline KNb 1-x Ta x O 3 solid solutions. SN Applied Sciences, 2020, 2 (11), ⟨10.1007/s42452-020-03673-3⟩. ⟨hal-03360783v2⟩