Layered SrTiO3/BaTiO3 composites with significantly enhanced dielectric permittivity and low loss

Ferroelectric ceramic materials are receiving increasing attention due to their extensive applications in electrical systems. In this work, three-layer BaTiO3/SrTiO3 ceramic composites consisting of one Ba1-xTiO3-SrxTiO3 (at x = 5, 10, 20 and 30) composite interlayer sandwiched by two BaTiO3 outer layers were fabricated. And the effects of SrTiO3 modification on their phase structures, microstructures and dielectric performance were studied in detail. A pure perovskite phase was observed in the Ba1-xTiO3-SrxTiO3 ceramic composites. The BaTiO3 ceramic doping by SrTiO3 exhibited refined grain size. With increased SrTiO3 content, both the permittivity and dielectric loss have increased. Furthermore, a layered structure was designed to enhance the dielectric properties. Conse-quently, a high permittivity of 7118 and low loss of 0.028 were achieved at 10 kHz in BaTiO3-30 w% SrTiO3-BaTiO3 three-layer ceramic composites. In summary, the introduction of SrTiO3 is believed to reduce the BaTiO3 Curie temperature and greatly improve its permittivity at room temperature. Furthermore, the accu-mulation of charge carriers at the interface significantly increases the permittivity, while preventing the trans-port of the charge carriers and reducing the loss. The ultrahigh permittivity and low loss make these composites promising candidates for microwave antennas, field effect transistors and dielectric capacitors.