Effect of tantalum substitution on the structural and electrical properties of BaBi8Ti7O27 intergrowth ceramics

Abstract

In this work, BaBi8(Ti1-xTax)7O27 (x = 0, 0.005, 0.01, 0.015, 0.02 and 0.03) intergrowth bismuth layer-structured ferroelectric ceramics (BLSFs) were prepared by traditional solid reaction method, and Ta5+ was designed to replace Ti4+ to regulate crystal structure and improve electrical properties. The results show that Ta5+ as a donor increases an orthogonal distortion, while reducing the concentration of oxygen vacancies in the ceramics.The results show that the structural distortion increases with Ta doping due to the larger radius of the Ta ion compared to that of the Ti ion. At the same time, proper Ta5+ doping as a donor can effectively inhibit the formation of oxygen vacancies, which reduces high temperature leakage, and can cause a sharp reduction of grain size. However, excessive Ta5+ doping also results in a serious structural distortion, and consequently a serious deterioration of electrical properties. BaBi8(Ti0.995Ta0.005)7O27 shows an optimal piezoelectric performance with a piezoelectric constant d33 of 19 pC/N, which is twice as large as that of pure BaBi8Ti7O27 (~8 pC/N), and verifies its possibility as a potential candidate material for high temperature piezoelectric field.