A linear relationship was found between the conductivity σ and Mn spin concentration x in pure AlPdMn single grains of high structural quality. The vanishing concentration of Mn spins (down to 4 x 10-5 moments) was associated with local defects in the Mn-atom local environment. Both σ and x were governed by the nominal composition, and could be reversibly tuned by careful heat treatment. It was deduced that the low σ characteristics of perfect AlPdMn quasicrystals could be observed only for concentrations of magnetic Mn lower than 5 x 10-4. That is, for defects which were more than about 30Å apart. In addition, it was shown that a Kondo-like effect explained a low-temperature σ increase; which was also linear in x.

Linear Increase of the Conductivity with the Concentration of Local Defects in AlPdMn Quasicrystals. J.J.Préjean, C.Berger, A.Sulpice, Y.Calvayrac: Physical Review B, 2002, 65[14], 140203 (4pp)