Dependence of electrical resistivity and magnetoresistance on long-range (F-type) ordering in Zn-Mg-Ho icosahedral quasicrystals

Electrical resistivity and magnetoresistance were measured in Zn60Mg30Ho10 icosahedral quasicrystals annealed at various temperatures that have differ ent degrees of long-range F-type ordering. In the temperature dependence of the electrical resistivity, the sample annealed at 832 K (higher annealing temperature) exhibits a broad maximum at 125 K, which can be interpreted o n the basis of the weak localization theory under strong spin-orbit effect. On the other hand, the samples annealed at lower temperatures have negativ e temperature coefficients of the resistivity in the whole temperature regi on between 2 K and room temperature. In the case of magnetoresistance, a gr adient of magnetoresistance above 40 kOe changes from negative to positive at low temperatures as annealing temperature is raised. Our present results indicate that the long-range F-type ordering systematically affects the be havior of electrical resistivity and magnetoresistance in the Zn60Mg30Ho10 icosahedral quasicrystal. (C) 2000 Elsevier Science B.V. All rights reserve d.