Ferroelectric and dielectric properties of bismuth-layered structural Sr2Bi4−xLnxTi5O18 (Ln=La, Nd, Sm and Dy) ceramics

Abstract La, Nd, Sm, and Dy-doped Sr 2 Bi 4 Ti 5 O 18 (SBTi) ceramic samples have been prepared by the solid-state reaction method. The X-ray diffraction reveals that all of the ceramic samples are single phase compounds. Their remnant polarization (2 P r ) increases at first, and then decreases with the increase of doping content. When doping content is 0.01, Sm and Dy-doped SBTi samples exhibit the maximum 2 P r of 18.2 and 20.1 μC/cm 2 , respectively. While La and Nd-doped SBTi samples display the maximum 2 P r value of 18.4 and 19.1 μC/cm 2 with doping content of 0.05 and 0.10, respectively. The ferroelectric properties of Sr 2 Bi 4− x Ln x Ti 5 O 18 are found to be dominated by the competition of the decrease of oxygen vacancy concentration and the relief of structural distortion.