Ni deposition on the pentagonal surface of an icosahedral Al–Pd–Mn quasicrystal

Abstract

We have evaporated Ni on the pentagonal surface of an icosahedral Al–Pd–Mn quasicrystal kept at room temperature. At the initial stage of growth, Ni intermixes with the substrate surface. Subsequently, Al from the quasicrystal matrix migrates to growing layers. The modified chemical composition in an initially icosahedral region near the surface induces a structural transformation. An Al–Pd–Mn alloy is formed which consists of five cubic domains with dimensions in the nm-range exposing their (1 1 0) faces parallel to the surface. These domains are azimuthally rotated by 2π/5 with respect to each other and aligned with symmetry directions of the icosahedral substrate. Al–Mn–Ni, Al–Ni, and Ni overlayers adopt both structure and orientation of these domains which stabilises Ni in a novel body-centred cubic phase. Ni-rich overlayers exhibit out-of-plane magnetic ordering.