Electron diffraction of ABX3 perovskites with both layered ordering of A cations and tilting of BX6 octahedra.
It is shown that 21 ABX(3) perovskites with tilted BX(6) octahedra and layered ordering of A cations can be generated on the basis of group-subgroup relations. These structures (with 16 different space groups) are classified into ten diffraction types in terms of the conditions for superstructure reflections caused by the ordering of A cations, tilting of BX(6) octahedra and structural absences. SAED (selected-area electron diffraction) allows the distinction of seven of the 21 different perovskites, while additional symmetry analysis by CBED (convergent-beam electron diffraction) is needed for the remaining 14 structures. The space groups of lithium lanthanum titanate pseudomorphs (with discrete chemical compositions) are successfully deduced by electron diffraction experiments.
Kishida
Kyosuke
K
Department of Materials Science and Engineering, Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan. k.kishida@materials.mbox.media.kyoto-u.ac.jp
Goto
Kengo
K
Inui
Haruyuki
H