Temperature dependence of the local piezoresponse in (K,Na)NbO3-based ceramics with large electromechanical strain

Abstract

We report on temperature dependence of local electromechanical properties of lead-free ( K,Na)NbO3-based ceramics that macroscopically manifests a large temperature-insensitive strain. Piezoresponse force microscopy reveals the particular role of the orthorhombic-tetragonal phase transition, where a reconstruction of the domain structure occurs and local piezoelectric response shows a peak value. A good quantitative agreement between temperature dependences of the local and previously reported macroscopic small-signal piezoelectric coefficients is observed. An influence of the polymorphic phase transition on polarization switching kinetics was revealed.