Dielectric and pyroelectric properties of the Ba_0.3Na_0.7Ti_0.3Nb_0.7O₃ ceramics obtained by sol-gel method

Abstract

The solid solution of barium titanate (BaTiO₃) and sodium niobate (NaNbO₃) -- Ba_1−x Na _x Ti_1−x Nb _x O₃ (BNTN) is a new lead-free material. BNTN ceramics obtained by the conventional ceramic method possess the classical ferroelectric behaviour when 0<x<0.075 and 0.55<x<1 and relaxor behaviour when 0.075 ≤ x ≤ 0.55 1. In this work we present the results of the investigations of the dielectric and pyroelectric properties of the Ba_1−x Na _x Ti_1−x Nb _x O₃ ceramics for x = 0.7 obtained, for the first time, from sol-gel derived powders. The temperature dependences of the dielectric permittivity ε′(T) within the frequency range 65 Hz–1 MHz and the pyroelectric current were investigated. The temperature range of the measurements was 90–470 K.

Keywords:

• Ba_1−x Na _x Ti_1−x Nb _x O₃
• BNTN
• Sol-gel synthesis
• Pyroelectric properties