Effects of Zn2+/Mg2+ ratio on dielectric properties of BaTiO3-based ceramics with excellent temperature stability: Experiments and the first-principle calculations

Abstract

To satisfy the development of MLCC devices, the dielectric properties and temperature stability of ceramic materials urgently needs to be improved. In our work, the 0.9BaTiO3-0.1Bi(ZnxMg0.5-xY0.5)O2.75 ceramics with x=0.0–0.5 are successfully prepared based on a traditional solid-state method. Meanwhile, the ceramic sample (core-shell structure) with x = 0.1 exhibits excellent dielectric properties and temperature stability (εr: 1207, tanδ: 0.009 and εr/ε25 ≤±15% within −80 to 200 °C), which satisfies the Electronic Industries Association (EIA) X9R (-55–150 °C, Δεr/ε25 ≤±15%) specification. In addition, the physical mechanism behind dielectric properties and temperature stability is systematic investigated based on experimental characterization and the first-principle calculations. The interface polarization is regarded as the primary cause affecting the dielectric properties, and has a close relationship with shell structure of ceramic samples. The lattice deformation of shell structure is caused by the introduction of heterovalent ions and non-equivalent substitution. Dielectric constant may be advance as content of Zn2+ ions increases due to the electronic enrichment around the zinc site in distorted lattice matrix. However, the weaken force between atom and electron results in the poor temperature stability.