Highly symmetric Mn sites in icosahedral Ti-Mn

We find that the ⁵⁵Mn NMR linewidth and Knight shift of icosahedral Ti₆₃{Mn}₃₇$ (i-TiMn) are identical to those of the crystalline phases obtained upon annealing. Comparison of the linewidth in i-TiMn and a bcc Ti-Mn solid solution shows that the Mn sites in both phases have a nearly cubic or higher symmetry. These measurements and our analysis provide strong evidence for a large density of structurally ordered, highly symmetric sites in an icosahedral alloy and demonstrate that a high degree of structural disorder is not an intrinsic property of the icosahedral phase.