Nano-scale oxygen octahedral tilting in 0.90(Bi1/2Na1/2)TiO3-0.05(Bi1/2K1/2)TiO3-0.05BaTiO3 lead-free perovskite piezoelectric ceramics

摘要

The oxygen octahedral tilted domains in0.90(Bi1/2Na1/2)TiO3-0.5(Bi1/2K1/2)TiO3-0.5BaTiO3 lead-free perovskitepiezoelectric ceramic have been studied by transmission electron microscopy(TEM). Selected-area electron diffraction patterns shows the 1/2ooo and 1/2ooereflections, indicating the presence of antiphase (a-a-a-) and in-phase(aoaoc+) octahedral tilting, respectively. The morphology and distributions ofthese tilted domains are shown in the centered dark-field images. Further, theBragg-filtered high-resolution TEM image reveals that the size of the in-phasetilted domains varies from 1 to 8 nm across. The ceramic contains the mixtureof non-tilted and variants of the antiphase and in-phase tilted domains.