コバルト系層状銅酸化物の規則・不規則構造の電顕観察

抄録

Crystal structures of Co-based layered cuprates, CoSr₂ (Y, Ce) _s8Cu₂O_5+2s (s=1-3), have been investigated by high-resolution electron microscopy (HREM) and electron diffraction (ED) techniques. For all the phases ED patterns showed double periodicity along a direction parallel to the CoO layers, indicating a regular alternation of two types of CoO₄-tetrahedra chains within the layers. Also seen was ordering of the chains along the layer-stacking direction for the s=1 phase. For the other phases the investigation revealed complete disordering of the chains along the layer-stacking direction. This implies that the interlayer ordering is mainly controlled by the distance between the neighboring CoO layers.