Nonuniform local magnetism in Al-Mn quasicrystals

The distribution of local magnetism in Al-Mn quasicrystal alloys has been studied by NMR spin-echo techniques. The ${}_{}{}^{55}{}_{}{}^{}\mathrm{Mn}$ resonance is found to be close to the position observed in non-magnetic orthorhombic ${\mathrm{Al}}_6$Mn and $\alpha -{\mathrm{Al}}_{73}{\mathrm{Si}}_{10}{\mathrm{Mn}}_{17}$ despite large paramagnetic susceptibilities in the quasicrystals. Analysis of spectral intensities shows that the paramagnetism is due to a class of Mn sites having local environments which do not occur in the crystals.