Experimental evidence for the existence of enhanced density of states and canonical spin-glass behavior in Al-Mn (-Si) quasicrystals

We report experimental evidence for an enhanced density of states at the Fermi level in ${\mathrm{Al}}_{86}$ ${\mathrm{Mn}}_{14}$ and ${\mathrm{Al}}_{75}$ ${\mathrm{Mn}}_{20}$ ${\mathrm{Si}}_5$ quasicrystals (QC) as indicated by the low-temperature specific heat and resistivity. The excess specific-heat term, Δγ, is proportional to the Mn concentration in these QC samples as is the case for dilute AlMn alloys. Spin-glass-like behavior is observed in both QC samples. In Al-Mn-Si, the relative frequency dependence of the ac susceptibility cusp is comparable to canonical spin glasses such as AgMn or CuMn.