Magnetic moment and spin glass behaviour of Al-Mn quasicrystals

Abstract

Al-Mn quasicrystals of several kinds of compositions were prepared by melt-quenching in order to investigate the magnetic properties. The curves of magnetic susceptibility against temperature were obtained and the effective magnetic moment P_eff was deduced from the Curie constant. With increasing Mn content from 14.3 to 22.5%, P_eff increases from 0.56 to 1.53 mu _B. The increment of P_eff becomes remarkable with the increase of Mn content. The spin glass behaviour, namely the cusp in the AC susceptibility curve, was observed above 20% Mn. The spin glass freezing temperature T_f increases from 3.3 to 8.5 K with increasing Mn content from 20.0 to 22.5% Mn. The magnetic moment is drastically reduced and the spin glass behaviour is eliminated, in the crystalline state, by annealing.