Dielectric properties of Ba0.6Sr0.4TiO3/Mg2SiO4/MgO composite ceramics -: art. no. 064107

The dielectric properties of BSTO/Mg2SiO4/MgO composite ceramics have been investigated systematically. The dielectric properties of BSTO composites under a dc bias field can be interpreted by the "soft-mode" theory near the phase transition and Johnson's phenomenological equation far above the transition temperature. Compared with most of the other BSTO composite ceramics, BSTO/Mg2SiO4/MgO not only can be sintered at a lower temperature but also keep a higher dielectric tunability versus a lower dielectric constant. For example, BSTO/35 wt. %Mg2SiO4/15 wt. %MgO has a dielectric tunability similar to 13.18% (under 2 kV/mm biasing) versus a dielectric constant epsilon(r(0))similar to 118.40 at 25 degrees C. It suggests that the dielectric properties are influenced to a great extent by the microstructure, and the dielectric tunability is enhanced when more continuous BSTO phase is obtained. (c) 2005 American Institute of Physics.