Crystal structure and ferroelectric properties of (Bi,La)4(Ti,Si)3O12 as a bulk ferroelectric material

We investigated the crystal structure, physical properties and ferroelectric performance of bulk material obtained by mixing and sintering Bi3.25La0.75Ti3O12 and Bi4Si3O12 or Bi2SiO5 for use as a novel ferroelectric material for ferroelectric memory. The resulting material was identified as a structure whereby, all of the peaks, as determined by powder X-ray and neutron diffraction, were the same as Bi3.25La0.75Ti3O12, and thus a single phase was obtained. Moreover, we investigated the crystal structure of the material by neutron diffraction, and the obtained results suggested that Si is substituted on Ti sites. The resulting material was investigated by SEM, and grains grown relative to Bi3.25La0.75Ti3O12 were observed. Based on P–E hysteresis measurements, this sample has a high remanent polarization (Pr) and a low coercive field (Ec) relative to Bi3.25La0.75Ti3O12, as well as improved overall ferroelectric characteristics.