Anisotropic Transport Properties of the Orthorhombic Al13Co4 Approximant to the Decagonal Quasicrystal

Anisotropic transport properties (electrical resistivity, thermoelectricpower, Hall coefficient and thermal conductivity) of the o-Al13Co4orthorhombic approximant to the decagonal phase were investigated. Thecrystalline-direction-dependent measurements were performed along the a,b and c directions of the orthorhombic unit cell, where (b, c) atomicplanes are stacked along the perpendicular a direction. Anisotropicelectrical and thermal conductivities are the highest along the stackinga direction. The anisotropic thermoelectric power changes sign with thecrystalline direction and so does the anisotropic Hall coefficient,which changes from the negative electron-like to the positive hole-likefor different combinations of the electric current and magnetic fielddirection. The transport properties of the o-Al13Co4 phase were comparedto the literature data on approximant to the decagonal quasicrystals,the Al76Co22Ni2 and the Al80Cr15Fe5, allowing for the study of evolutionof transport properties with increasing structural complexity and unitcell size.