Systematics of Disorder in Quasiperiodic Material

We report new x-ray scattering data on AlMn alloys. None of our samples are perfect quasicrystals; all have finite-width x-ray peaks. Specific preparation techniques lead to samples with peak widths which correlate strongly with $G_{\perp }$ (phason momentum). We show that the data are consistent with either frozen-in phason strain or random icosahedral packing. These two models predict surprisingly similar but potentially distinguishable scattering widths, differing in their detailed dependence on $G_{\perp }$.