Growth and physical properties of the decagonal Al–Cu–Co quasicrystal grown from the ternary melt

Abstract

Large faceted single-grain quasicrystals of the approximate composition Al63.2Cu19.5Co17.3 and with a high degree of structural perfection are obtained through the slow cooling of a ternary melt with initial composition Al65Cu29Co6. X-ray diffraction patterns of crushed single-grain samples are exceptionally sharp, indicating a high degree of structural order, with no evidence of secondary phases. Transmission electron micrographs also reveal sharp diffraction patterns in the even-n layers but diffuse scattering in the odd-n layers. Temperature-dependent magnetization, electrical resistivity and specific heat are measured using bars cut perpendicular and parallel to the c axis and show diamagnetic behaviour: γ ≈ 0.5 mJ mol−1 K−2, ρ c(2 K) ≈ 52 μΩ cm and ρ q(2 K) ≈ 283 μΩ cm.