Ferromagnetism in icosahedral Al-Mn-Si alloys

Alloys of ${\mathrm{Al}}_{50}$ ${\mathrm{Mn}}_{20}$ ${\mathrm{Si}}_{30}$ and ${\mathrm{Al}}_{55}$ ${\mathrm{Mn}}_{20}$ ${\mathrm{Si}}_{25}$ have been prepared by rapid quenching from the melt onto a single Cu roller. As-quenched alloys have been found to be fully amorphous. This amorphous phase crystallizes at approximately 600 K. Alloys annealed below the crystallization temperature transform into single-phase icosahedral quasicrystals. Both the amorphous and quasicrystalline phases are weakly ferromagnetic with Curie temperatures around 120 K and saturation magnetization in the order of 0.1 emu/g.