Structure and magnetism of quasicrystalline and crystallineAl1−xMnxalloys

Abstract

We have performed x-ray structural studies of quenched and annealed ${\mathrm{Al}}_{1-x}{\mathrm{Mn}}_x$ alloys in the range of $0.14\le x\le 0.20$. The quenched samples exhibit a coexistence of Al with an icosahedral phase, the latter having a maximum volume fraction at $x=0.20\mathrm{}$. Magnetic susceptibility measurements for $x=0.14\mathrm{} \mathrm{and} 0.20$ show a dramatically enhanced magnetic moment in the icosahedral phase ($p=0.747\mathrm{} \mathrm{and} 1.27, \mathrm{respectively}$) as compared to the annealed samples ($p=0\mathrm{} \mathrm{and} 0.617, \mathrm{respectively}$). The increase of magnetic moment per Mn ion with increasing Mn concentration indicates a range of stoichometries and microstructures over which the icosahedral phase can exist.