Synthesis and cationic ordering structure of samarium-doped lead magnesium niobate ceramics

The pyrochlore-free 10 mol% Sm2O3-doped/undoped Pb(Mg13Nb23)O3 ceramics were fabricated and their cationic ordering structures were investigated by X-ray/electron diffraction techniques. In the X-ray diffraction patterns, only fundamental diffraction peaks were observed for the undoped Pb(Mg13Nb23)O3, while the (h + 12 k + 12 l + 12) superlattice reflections were also observed for the 10 mol% Sm2O3-doped Pb(Mg13Nb23)O3. In the electron diffraction patterns, the (h + 12 k + 12 l + 12) superlattice reflections as well as the fundamental diffraction spots were observed for the undoped and the 10 mol% Sm2O3-doped Pb(Mg13Nb23)O3, but the intensities of the superlattice reflections were stronger for the 10 mol% Sm2O3-doped Pb(Mg13Nb23)O3. It has been experimentally assured that Sm-doping enhances the 1:1 ordering of Mg2+ and Nb5+ ions in Pb(Mg13Nb23)O3.