Dielectric properties and crystallite size distribution of modified lead-free sodium-bismuth titanate ceramics

Abstract

Influence of (K_0.5Bi_0.5)TiO₃ (KBT) dopants on crystal and microstructure, ferroelectric and dielectric properties of ceramic composition from morphotropic phase boundary in the system (1–x–y)(Na_0.5Bi_0.5)TiO₃ – xBaTiO₃ – y(K_0.5Bi_0.5)TiO₃ (x = 0.06, y = 0–0.15) additionally modified by ZnO additives was studied using a complex of methods. Changes from 42.8 nm to 62.6 nm of the volume-weighted crystallite size distribution function G(L) corresponding to coherent scattering regions were observed. The microstructure and the second harmonic generation data indicated a change in the relative content of polar nanoregions in tetragonal nonpolar matrix. Decrease in temperatures of phase transitions T_m and T_d was observed with KBT concentration increasing.

Keywords:

• Sodium-potassium niobate
• perovskite structure
• crystallite size
• dielectric properties

Additional information

Funding

The work was supported by RFBR and DFG (project number 21-53-12005) and by the Ministry of Science and Higher Education of the Russian Federation for the Russian Academy of Sciences (No. 45.22 AAAA-A18-118012390045-2), and within the state assignment FSRC “Crystallography and Photonics” RAS.