The structure of Sr2NdNbCu2O8 (tetragonal, space group P4bm, a = 0.549, c = 1.166 nm) and crystallographic defects occurring therein have been studied with high resolution electron microscopy and electron diffraction. The structure of Sr2NdNbCu2O8 consists of a layer sequence NdCuO2SrONbO2SrOCuO2 having a perovskite-like structure. This structure is very similar to that of YBa2Cu3O7: Y is replaced by Nd and the CuO layer by a NbO2 layer. Sr2NdNbCu2O8 has an ap√2, ap√2, c superstructure, due to rotation of the NbO6 octahedra about the c-axis, leading to a space group P4bm. This superstructure is often short range. Intergrowths occur with an approximate composition of Sr(Nb, Cu)O3, which adopts a modified simple perovskite structure. Also, examples are shown of  90° rotation twins and edge dislocations.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry