[13a-D519-1~10] 9.1 Dielectrics, ferroelectrics

[13a-D519-5] Fabrication and Evaluation of Ferroelectric Property of K(Ta, Nb)Si₂O₇ Single Crystals

〇(M2)Miho Onuma¹, Hiroaki Takeda¹, Takaaki Tsurumi¹, Takuya Hoshina¹ (1.Tokyo Tech.)

Keywords:ferroelectric, single crystal, silicate compound

KNbSi₂O₇(KNS)is a novel ferroelectric material having a structure in which SiO₄ tetrahedron enters between perovskite structures. In this study, we fabricated single crystals of KTa_xNb_1-xSi₂O₇(KTNS, x=0-0.3) in which a part of Nb ions was substituted with Ta, and measured the ferroelectricity. As a result of polarization measurement, the spontaneous polarization seemed to increase with increasing the amount of Ta. In contrast, the theoretical spontaneous polarization obtained using First-principles calculations indicated the opposite trend. We discussed in detail the intrinsic ferroelectricity of KTNS based on the results of polarization measurements at high temperatures and hot poling treatment.