The tunability in (Ba, Sr)TiO3-Mg2TiO4 system

(Ba, Sr)TiO3-Mg2TiO4 composite ceramics were fabricated via solid-state reaction method. X-ray diffraction, scanning electron microscopy and Raman spectroscopy were used to characterize the phase compositions and microstructures. The dielectric characteristics and tunability of composite ceramics were investigated. Depending on the tunability, the composition of (Ba, Sr)TiO3-Mg2TiO4 can be divided into three regions: initial decreasing region, unusual increasing region and final decreasing region. This unusual increased tunability is due to electric field redistribution caused by composite effect, that is proved by the simulation result. Moreover, the change of Curie temperature also has a great impact on the tunability in this region.