IMF2017

For the past 40-50 years, lead based perovskite Pb(Zr_xTi_1-x)O₃ (PZT) piezoelectric ceramics have dominated the commercial market of piezoelectric devices due to their remarkable dielectric and piezoelectric properties and ability to operate in wide temperature range. But due to environmental concerns the use of PZT in the European Union was limited. In our presentation broadband dielectric properties of BaTiO₃ (BT) based composites with core-shell superstructure in temperature range of 100 to 500 K will be presented. The composites were prepared in two steps. BT, BiFeO₃ (BF), BaTiO₃-Bi(Mg_0.5,Ti_0.5)O₃ (BT-BMT) and BaTiO₃-Bi(Mg_0.5,Ti_0.5)O₃-BiFeO₃ (BT-BMT-BF) nanoparticles were compressed into low density pellets and head treated to create a necking structure. Then using solvothermal reaction method the epitaxial layer of BT was deposited around BT, BF, BT-BMT and BT-BMT-BF particles. In such systems cores are stressed by barium titanate shell creating similar conditions as in morphotropic phase boundary (MPB), thus increasing dielectric and piezoelectric constants. We have investigated 4 different composite systems where core is a good dielectric, a relaxor, a ferroelectric and a non-ferroelectric material.