ELECTRICAL RESISTIVITIES OF STABLE QUASI-CRYSTALS

As x decreases in Al5(Li(1-x)Mg(x))3.5-4Cu I-phases, and annealing temperature increases in Al68Cu17Ru15 I-phase, the quality of the phase is increased, the electrical resistivity rho increases drastically up to 870-2500 mu-OMEGA-cm at 4.2 K, and the temperature coefficient of rho decreases. For the highest quality samples in both alloy systems, the temperature and magnetic field dependences of rho are consistent with the theory of a weak localization. In single-grained Al70Ni15Co15 and Al62Cu20Co15Si3 D-phases, a large anisotropy is observed both in the resistivity and the magnetic susceptibility. These results are interpreted by the presence of a structure-induced pseudogap of electron density of states at the Fermi level and a localization tendency of electrons near the pseudogap.