Influence of tungsten doping on dielectric properties of strontium bismuth niobate ferroelectric ceramics

The influence of tungsten doping on the dielectric properties of SBN ferroelectric ceramics was studied. X-ray diffraction was used to determine the formation of layered perovskite phase after firing. For the electrical property measurements, the sintered pellets were polished to have flat and parallel surfaces at both sides with a thickness of ∼1 mm. The dielectric constant and loss tangent as functions of temperature up to 600°C and frequency ranging from 20 Hz to 1 MHz were measured. Dielectric constant gradually increased with an increasing concentration of tungsten. In addition, a low concentration of tungsten was likely to introduce space charge polarization into the system, resulting in an appreciable decrease in both dielectric constant and tangent loss as frequencies reduced from 20 Hz to 1 kHz.