Periodic superorder and disorder of decagonal Al[sbnd]Ni[sbnd]Co and Al[sbnd]Co[sbnd]Cu([sbnd]Si) phases

Commensurate satellite reflections in diffraction patterns of decagonal Al-Ni-Co and Al-Cu-Co phases indicate a periodic superorder on the quasiperiodic substructure. From the intensity characteristics of these satellites a box-like modulation function is derived which may be visualized in different ways including approximant phases. An interpretation by fine-scale periodic lamella microdomains matches closely high-resolution electron microscopy observations and characteristic structural features of the average structure.