Anisotropic local structure of decagonal quasicrystals by DAFS

Abstract

Diffraction anomalous fine structure (DAFS) analyses were performed on Al-Ni-Co (ANC) and Al-Ni-Fe (ANF) decagonal quasicrystals at the K-edges of Ni, Co and Fe. In ANC, an order-disorder phase transition with anisotropic atomic short-range order (SRO) is clearly recognizable at high temperature. During in situ observation, a zigzag correlation along the periodic direction developed during the early stage of ordering. Far above the phase transition temperature, this weak correlation along the periodic direction is independent of other correlations along the quasiperiodic one. In ANF, SRO of Fe developed along the quasiperiodic direction, although the local environment of Ni was almost random.