Pressure dependence of the low-frequency dielectric constant of KNbO_3

TL;DR

This study examines how pressure affects the low-frequency dielectric constant of KNbO_3, revealing a peak at 22.5 kbar linked to a phase transition, with irreversible changes upon decompression.

Contribution

It provides the first detailed measurement of pressure-dependent dielectric behavior of KNbO_3, highlighting a pressure-induced phase transition and hysteresis effects.

Findings

Dielectric constant increases with pressure up to 22.5 kbar

Maximum dielectric constant of 5000 at 22.5 kbar

Irreversible phase change observed upon decompression

Abstract

The effect of pressure on the low-frequency dielectric constant, $\epsilon_0$, of single crystals of KNbO_3 is investigated by means of capacitance measurements. The dielectric constant increases with pressure up to 22.5 kbar, where it exhibits a large value ($\epsilon_0$ = 5000), and then decreases. This change in its behaviour is related to a phase transition induced by pressure. On decompression, the samples do not revert back to the ambient pressure phase.