Effect of Dy-doping on the properties of Sr2Bi4Ti5O18 ferroelectric ceramics

Ferroelectric Sr 2 Bi 4-x Dy x Ti 5 O 18 (SBDT-x, x= 0—0.20) ceramic samples were prepared using the conventional solid-state reaction method. x-ray diffraction patterns (XRD) of SBDT-x ceramics show that doping with a small amount of Dy does not change the crystal structur e of Sr 2 Bi 4 Ti 5 O 18 (SBTi). Their Curi e temperature (T c ) and dielectric loss (tanδ) decrease with Dy dopin g amount. The remnant polarization (2P r ) of SBDT-x increases at first , then decreases with increasing of Dy content. When Dy content is 0.01, the 2P r reaches a maximum value of 20.1 μC·cm -2 . The variation of 2P r for SBDT-x relates to space charge density, internal strain an d structure distortion. (Bi 2 O 2 ) 2+ layer acting as an insulating layer and space charge storage plays an important role in their ferroelectric properties in BLSFs. The incorporation of doping ions into (Bi 2 O 2 ) 2+ layer may destroy its original function and deteriorate the ferroelectric property.