Fabrication of ferroelectric silicate KNbSi2O7 single crystal

Abstract

ABSi2O7 is a new ferroelectric material group of which ferroelectricity has been discovered recently. In this study, we focused on potassium niobate silicate (KNbSi2O7 ), which comprises displacement-type ferroelectric substance KNbO3 and high-covalence substance SiO 2 in the structure. KNbSi2O7 single crystals with a size of 10 × 10 × 1mm3 were fabricated by the process of glass crystallization, re-melting, and slow-cooling. The polarization-electric field (P-E) curve of the KNbSi2O7 crystal was evaluated and KNbSi2O7 evidently showed ferroelectricity in the direction of c axis. The value of the spontaneous polarization was estimated to 0.11μC/cm2. The dielectric permittivity was approximately 15 for both a and c axes at 1 MHz, and this material was found to be a ferroelectric material with low dielectric permittivity. © 2014 The Ceramic Society of Japan.