Anisotropic electrical, thermal and magnetic properties of Al13Ru4 decagonal quasicrystalline approximant

Abstract

Abstract We present measurements of the anisotropic electrical and thermal transport coefficients (the electrical resistivity, the thermoelectric power, the thermal conductivity), the magnetization and the specific heat of the Al13Ru4 monoclinic approximant to the decagonal quasicrystal, in comparison to the isostructural Al13Fe4. The electrical and thermal transport parameters of Al13Ru4 were found to exhibit significant anisotropy, qualitatively similar to that found previously in the Al13Fe4 (P. Popčević, et al., Phys. Rev. B 2010, 81, 184203). The crystallographic b direction, corresponding to the stacking direction of the (a,c) atomic planes, is the most conducting direction for the electricity and heat. The thermopower is strongly anisotropic with a complicated temperature dependence, exhibiting maxima, minima, crossovers and sign change. The electronic density of states (DOS) at the Fermi energy is reduced to 35% of the DOS of Al metal. The magnetic susceptibility is diamagnetic and the diamagnetism is by a factor of 2 stronger for the magnetic field along the stacking b direction.