Labyrinth pattern in a decagonal quasicrystal

The unique properties of quasicrystals are closely related with their complex crystal structures and microstructures. Here, we report the labyrinth structures of decagonal quasicrystal in Al68Cr26Si6, which is scarcely found in quasicrystals. An electron microscopic study of as-cast Al68Cr26Si6 shows a structure of quasiperiodic nanodomains with overall decagonal diffraction symmetry. The quasiperiodic nanodomains are separated by a labyrinthine pattern of edge -connected structural building blocks shaped like squashed (fat) hexagons. The arrangement of the domain walls resembles that of ferroelectric or magnetic domain structures, although these are of different origin and on different scales. By annealing Al68Cr26Si6 at 1,223 K, the domain wall density is strongly increased and appears to be arranged periodically in a specific way.