Growth and characterization of large size lead‐free ferroelectric K(Ta,Nb)O₃ single crystal

Abstract

Lead-free piezoelectric materials with excellent performance are greatly demanded for the environmental issues. The lead-free ferroelectric single crystals are therefore greatly concerned for their much higher piezoelectricity than the polycrystalline counterparts and the domain-tunable property. However, the growth of large size and high-quality lead-free ferroelectric crystals has always been a great challenge. In this work, a ferroelectric KTa 1x Nb x O 3 (KTN) single crystal with an extremely large size of 25 × 25 × 37 mm 3 was grown using the modified top-seeded solution growth method. The large size enabled us to carry out comprehensive investigations on the crystal. The complete sets of dielectric, piezoelectric, and elastic constants for the [001] C -poled KTN crystal with quasi single domain state were determined. Results showed that the crystal exhibits high electromechanical coupling coefficients with k t~0 .642 and k 33~0 .679. Furthermore, the orientation dependence of the piezoelectric, dielectric, and elastic properties was determined by the tensor matrix transformation technique, and the maximum d 33 , s E 33 , and k 33 were found along the polar direction [001] C . This work not only provides important guidance for the growth technology of lead-free ferroelectric crystals but also offers essential datasets of lead-free alkali niobate system, which is of great importance for both theoretical studies and designs of electromechanical devices. K E Y W O R D S ferroelectric KTa 1x Nb x O 3 single crystal, full tensor properties, lead-free piezoelectric materials How to cite this article: Zhang Y, Li S, Liu F, et al. Growth and characterization of large size lead-free ferroelectric K(Ta,Nb)O 3 single crystal.

Cu-Doping-Modified Order State, Ferroelectric Property, Multiscale Inhomogeneities, and Local Structure in the Relaxor KTa1–xNbxO3 Crystal

“…33 The exchange−correlation potential generalized gradient approximation of Perdew−Burke−Ernzerhof is applied to describe the electron− electron interactions. The valence states used for the calculations are 3s 2 3p 6 4s 1 for K, 5p 6 5d 3 6s 2 for Ta, 4d 5 5s 1 for Nb, and 2s 2 2p 4 for O. The cutoff energy for wave functions was set to be 600 eV.…”

“…KTa 1– x Nb x O 3 (KTN) belongs to a lead-free relaxor ferroelectric, a vital functional crystal, avoiding the pollution to the environment because of the high toxicity of lead. It has wide-ranging applications in industrial and medical fields, including electro-optic (EO) modulators, , deflectors owing to the giant EO effect and high transparency in the wide spectrum, good performance actuators, and ultrabroad-band ultrasonic imaging transducers because of excellent dielectric, piezoelectric, and electrostrictive properties . These fascinating features are closely related to polar nanoregions (PNRs) condensed by a large amount of off-center B-site Nb ions.…”

“…It has wideranging applications in industrial and medical fields, including electro-optic (EO) modulators, 1,2 deflectors 3 owing to the giant EO effect and high transparency in the wide spectrum, good performance actuators, and ultrabroad-band ultrasonic imaging transducers because of excellent dielectric, piezoelectric, and electrostrictive properties. 4 These fascinating features are closely related to polar nanoregions (PNRs) condensed by a large amount of off-center B-site Nb ions. Implementing the cool-down operation from high temperature, the PNRs with zero time-averaged polarization appears near Burns temperature T B and is insensitive to the external electric field because of violent thermal fluctuation.…”

Elasto‐Optic Effect of Lanthanum‐Modified Lead Zirconate–Lead Titanate Transparent Ceramics: Application in Optical‐Stress Sensors

“…Consequently, large and optically homogenous materials cannot be prepared, which hinder the development and application of these materials. [ 25–30 ] Therefore, developing new elasto‐optic materials is essential. In 2014, Abhijeet et al.…”