High permittivity behavior and microstructure in a two-phase barium-silicon titanate

Barium titanate (140 nm) was coated with silicon dioxide using atomic layer deposition after which the powders were sintered at 1050 °C for 5 min at 50 MPa using a direct current sintering furnace. Dielectric measurements showed large permittivity (up to 4 × 105) with X-ray and electron diffraction confirming a cubic titanate and tetragonal silicate-based mixture. Transmission electron microscopy revealed planar faults within the tetragonal phase where such defects could assist in the charge storage along with grain boundaries. Polaron relaxation was also observed in this material.