IMF2017

High piezoelectric activity is of high demand for various applications. The desired properties are most often observed in solid solutions displaying the so-called Morphotropic Phase Boundary (MPB), when two different lattice structures are of similar energy, thus extrinsic stimulus leads to easy deformation. However, not all solid solutions exhibit the MPB. As a result artificial MPBs are of high interest, and they can be formed in ferroelectric composites. BaTiO₃ (BT) and KNbO₃ (KN) were selected as the starting members, as they are both lead-free ferroelectrics and have dissimilar lattice structures at room temperature. Creating epitaxial interfaces with KN inside BT structure creates stresses that increases domain wall count and, as a result, piezoelectric coefficient. Composites were prepared in two steps: cold-pressed BT particles were heated to 1000 °C for 2 h to create low-density ceramics, then KN were epitaxially deposited to BT structure. In this presentation dielectric properties of BT-KN with different KN molar ratios will be presented. It was found, that the piezoelectric effect gives a significant contribution to the total dielectric permittivity. Impact of KN on the piezoelectricity of the strained BT was obtained and compared.