Non-linear dielectric coefficients of free and clamped barium titanate crystals

Abstract

The free and clamped higher order dielectric coefficients of barium titanate (BTi, BSi, CTi, CSi) are determined by measuring the field dependence of polarisation within the double loop region. For this purpose pulses were applied to the samples with rise times which are long and short compared to the transit time of the electrostrictively excited mechanical pulses. The difference BSi–BTi = 4.5 × 108 – (−8) × 108 = 12.5 × 108 m5V/C3 satisfactorily agrees with the value calculated from eletrostrictive and elastic coefficients.

Quantum annealed criticality: A scaling description

“…22 An experimental setting for this behavior is provided by BaT iO 3 with a classical ferroelectric phase transition that is continuous when clamped and, due to electromechanical coupling, becomes first-order when unclamped. 23,24 Low-temperature measurements on ferroelectric insu-arXiv:2012.01601v1 [cond-mat.str-el] 2 Dec 2020 lators provide a key motivation for our study. [17][18][19][20][21] At finite temperatures and ambient pressure these materials often display first-order transitions due to strong electromechanical coupling; 24 yet in many cases [17][18][19][20][21] their dielectric susceptibilities suggest the presence of pressure-induced quantum criticality associated with zero-temperature continuous transitions.…”