engleski

Origin of the anisotropy in the transport properties of the Al13TM4 complex intermetallics

Transport properties (electrical resistivity, thermoelectric power, and thermal conductivity) of the monoclinic Y-Al-Co-Ni[1], orthorhombic o-Al13Co4[2], monoclinic m-Al13Fe4 and m-Al13(Fe, Ni)4[3], which belong to the Al13TM4 (TM=transition metal) class of approximants to decagonal phases have been investigated. They are characterized by a very large unit cell size and with the large structural complexity. Common to all investigated intermetallics is strong anisotropy of the transport properties which is qualitatively similar to the decagonal quasicrystals d-Al-Ni-Co[4]. The approximants to decagonal phases and decagonal quasicrystals have similar structural details on the atomic scale and one set of the atomic planes that is stacked periodically with the same periodicity length. The stacked-layer structure appears to be origin of the anisotropic transport properties of the Al13TM4 complex intermetallics, whereas the in-plane structural details seem to be of marginal importance. The results for Al13TM4 are compared with the recently obtained results for the single crystal of structurally similar Taylor phase T-Al11(MnFe)4[5] and single crystal of decagonal quasicrystal d-Al77Co6Ni17 [6]. [1] A. Smontara, et al. ; Phys. Rev. B, 78 (2008) 104204. [2] J. Dolinšek, et al. ; Phys. Rev. B, 79 (2009) 184201. [3] P. Popčević, et al. ; Phys. Rev. B, 81 (2010) 184203. [4] S. Martin, et. al. ; Phys. Rev. Lett. 67 (1991) 719. [5] M. Heggen, et al. ; Phys. Rev. B, 81 (2010) 184204. [6] P. Popčević, K. Velebit and A. Smontara, unpublished results.

approximants of the decagonal quasicrystal ; transport properties ; anisotropy

The paper was presented at the First European Integrated Center for the Development of New Metallic Alloys and Compounds Days (C-MAC) as a talk by Petar Popčević. This work was done within the activities of the European Integrated Center for the Development of New Metallic Alloys and Compounds - C-MAC.