Effects of Er3+-doping on dielectric and piezoelectric properties of 0.5Ba0.9Ca0.1TiO3-0.5BaTi0.88Zr0.12O3-0.12%La-xEr lead-free ceramics

0.5Ba(0.9)Ca(0.1)TiO(3)-0.5BaTi(0.88)Zr(0.12)O(3)-0.12%La-xEr (x = 0-0.5%) lead-free ceramics were prepared by a modified Pechini polymeric precursor method, and the effects of erbium contents (x) on the crystal structure, dielectric and piezoelectric properties were investigated. The samples showed high densification (relative density: similar to 96.6%) with fine grain size (similar to 0.652 mu m) under the synthesis conditions at x = 0.2%. The Curie temperature (T-C) shifted toward lower temperature and orthorhombic-to-tetragonal phase transition temperature (TO-T) shifted toward higher temperature with addition of x, which was beneficial for elevating piezoelectric properties as pinched effect of the temperature. The diffuseness of the ceramics was receded with a small addition of x, because of disappeared oxygen vacancy and small area of polar nano-regions (PNRs) in the structure. The elevated piezoelectric constant (d(33); similar to 200 pC/N) and receded mechanical quality factor (Q(m); similar to 70) at x = 0.2% showed softening effect by donor doping. However, erbium showed hardening effect by accepter doping with the substitution of B sites in the matrix of ABO(3) structure with excessive erbium contents. (C) 2016 Elsevier B.V. All rights reserved.