Magnetic and electrical properties of icosahedral quasicrystalline Al-Mn alloys

Abstract

Al-Mn quasicrystals having icosahedral structure were prepared by melt-quenching, and the magnetic and electrical properties of both quenched and annealed specimens were investigated. The magnitude of the localised magnetic moments of Mn deduced from the Curie constant was qualitatively explained on the basis of the Pauling valence. A cusp in the AC susceptibility of the spin-glass was observed at 85K in Al-22.5 at.% Mn quenched alloy. The magnetisation curves measured at low temperatures for both quenched and annealed alloys exhibited some external magnetic field dependence because of the existence of the RKKY interaction. The electrical resistivity of Al-22.5 at.% Mn quenched alloy was extremely large at about 970 mu Omega cm due to the non-periodic potential caused by no long-range translational symmetry in the icosahedral quasicrystalline structure and to the resonance state of the Fermi electrons with the d state of Mn.