SHORT-RANGE ORDER IN AGED AL-MN QUASICRYSTALS

Recently, N. K. Mukhopadhyay et al. have reported diffuse scattering that develops upon low-temperature annealing of icosahedral i(AlMn). The known quasicrystals all have diffraction patterns with the same spot positions as that of the three-dimensional Penrose tiling (3DPT) of rhombohedra; along odd-parity (threefold and fivefold) directions, bright spot positions form a sequence increasing by powers of tau **3 ( tau EQUVLNT (1 plus ROOT 5)/2). The new diffuse spots occur along these axes at multiples tau and tau ** minus **1 of the positions of the sharp spots. A simple interpretation of this phenomenon in terms of the structural model derived from alpha (AlMnSi) is proposed. 15 Refs.