Stability of electronic states in the layered perovskite Sr2−xNdxMnO4

The electronic system in the layered perovskite Sr2−xNdxMnO4 is characterized as a two-dimensional eg-electron system. In order to understand the stability of electronic states in the Nd-content region of 0 ⩽ x ⩽ 0.50, the crystallographic features of this manganite have been investigated by transmission electron microscopy. The increase in the Nd-content led to the orbital ordered state in 0.10 ⩽ x ⩽ 0.25 and the charge and orbital ordered state in 0.25 ⩽ x < 0.45. In particular, it was found that the orbital ordering accompanied the C-type antiferromagnetic ordering at lower temperatures, and that the transition to the charge and orbital ordered states was strongly suppressed in x > 0.35.