Microdomain structure in the disordered Zn-Mg-Ho icosahedral phase

Diffuse scattering related to F-type superlattice ordering was observed in the disordered icosahedral phase formed in Zn60Mg35Ho5 alloy annealed at 562 degrees C. Real space analysis of the diffuse scattering was carried out using high-resolution electron microscopy and a Fourier filtering method. Processed images revealed the presence of microdomains related to weak F-type ordering. The domain diameters range between 30 and 170 Angstrom. Each domain is separated by a boundary region, and is related to nearby domains by an antiphase relationship. These results indicate that the origin of the diffuse scattering is the presence of these domains rather than statistical homogeneous short-range ordering.