Phase transition-induced high electromechanical activity in [(K0.5Na0.5)1-xLix](Nb0.8Ta0.2)O3 lead-free ceramic system

A high electromechanical activity is observed in the [(K0.5Na0.5)(1-x)Li-x](Nb0.8Ta0.2)O-3 (x = 0, 0.02, and 0.03) lead-free ceramic system at and around the orthorhombic (O)-tetragonal (T) phase transition temperature (TO-T). This activity is found to originate from an O-T phase transition region at ambient temperature rather than a classical morphotropic phase boundary (MPB) region intrinsic in the Pb(Zr1-xTix)O-3 (PZT) lead-based ceramic system. Li modification enables a large decrease in TO-T instead of constituting a classical MPB. In contrast to the nearly temperature-independent classical MPB behavior in the PZT system, the strong temperature-dependent phase transition behavior in the system may impose a challenge to temperature demanding applications. (C) 2009 Elsevier B.V. All rights reserved.