Effects of CuO Addition on Electrical Properties of 0.6BiFeO₃–0.4(Bi_0.5K_0.5)TiO₃ Lead‐Free Piezoelectric Ceramics

Abstract

0.6BiFeO3–0.4(Bi0.5K0.5)TiO3 (0.6BF–0.4BKT) ceramic samples with 0.0–4.0 mol% CuO were prepared by the solid‐state reaction. The CuO addition aided the densification of the samples and slightly increased the lattice constant. The relaxor‐like defuse dielectric peak of 0.6BF–0.4BKT became sharper with increasing the CuO content. Polarization–electric field curve of the undoped 0.6BF–0.4BKT was a pinched loop in the as‐sintered state, while that was a square hysteresis with a large remanent polarization of 48 μC/cm2 after the thermal quenching, demonstrating a strong domain wall pinning due to defect dipoles. We found that the CuO addition up to 2.0 mol% facilitates the polarization switching in the as‐sintered samples to increase the remanent polarization and the piezoelectric d33 coefficient. The results of the structural and electrical investigations suggested that the copper ion acts as a donor in 0.6BF–0.4BKT by compensating the potassium vacancy created by the evaporation of K2O during the calcination and sintering processes.

Electrical properties and low temperature sintering of BiAlO3 doped (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 lead-free piezoelectric ceramics

“…However, low density, low temperature stability and relatively low piezoelectric properties as compared with those of PZT-based ceramics hinder their practical applications [3][4][5]. Therefore, it is desirable to explore a new lead-free system with higher piezoelectric properties to replace PZTbased ceramics.…”

Enhancement of electrical properties in the ternary PMN–PT–PZ through compositional variation, crystallographic texture, and quenching

“…However, these mobile and positively charged () point defects may move around the structure and form defect dipoles with the immobile lead vacancies (). As the material slowly cools down through the Curie temperature, ferroelectric domains develop and defect dipoles would inherently prefer to align with the polarization vector of the domain, resulting in the stabilization of the domain structure . The defect dipoles may also be redistributed along the low energy domain boundaries, again pinning the domain walls .…”

“…As the material slowly cools down through the Curie temperature, ferroelectric domains develop and defect dipoles would inherently prefer to align with the polarization vector of the domain, resulting in the stabilization of the domain structure. 12 The defect dipoles may also be redistributed along the low energy domain boundaries, again pinning the domain walls. 13 This may lead to the appearance of an internal bias (E int ), as it was observed in our case.…”

Dielectric and ferroelectric properties of CuO-doped lead magnesium niobate-based relaxor ferroelectric ceramics

“…18 In the literature, sintering additives are frequently adopted to lower the sintering temperature. According to the nature of the additives, there are two kinds of sintering additives, i.e., low melting point metal oxides (such as CuO) [19][20][21][22][23] and glass-phase additives. [24][25][26][27][28][29][30] Compared to the complex chemical compositions of glass additives, the effect of CuO for low-temperature sintering has been systematically studied in many ferroelectric systems.…”