Properties of tungsten-doped Bi4Ti3O12-SrBi4Ti4O15 intergrowth ferroelectrics

Ferroelectric and dielectric properties of tungsten-doped Bi{sub 4}Ti{sub 3}O{sub 12}-SrBi{sub 4}Ti{sub 4}O{sub 15} ceramics were investigated. A pure phase of all the samples is confirmed by X-ray diffraction patterns. The remanent polarization (2P {sub r}) of the samples increases initially and reaches its maximum value of 43.2 {mu}C/cm{sup 2} when W content is 0.03, which is over twice as large as that of non-doped one, then decreases with further doping. The coercive field (E {sub c}) shows a weak tungsten content dependency. It is considered that the enlarged 2P {sub r} could be mainly attributed to the restraint of oxygen vacancies as well as the weakening of their mobility. The Curie temperature decreases a little with increasing doping content, which indicates the good thermal stability is not deteriorated by tungsten doping.