Anomalous transport properties in pure alcufe icosahedral phases of high structural quality

A very high-resistivity value (ρ_4k~4300 μΩcm), associated to a strong negative temperature dependence (∞ = l/ρ ∆ρ/∆ρ ~-10^-3K^-1), is measured in pure icosahedral A1₆₃C_u25Fe₁₂ phases (a single grain and polyq&erystalline samples). Moreover the resistivity of the defective as-quenched A1₆₃C_u25Fe₁₂ samples is much smaller (ρ_4k~1300 μΩcm) and increases sharply (up to -4300 μΩcm) after annealing treatment. We show also that the temperature and magnetic-field dependences of the resistivity and the Hall effect can be analysed through electron-electron interactions and localization theories.