Low-temperature specific heat and anisotropy of the thermal conductivity of decagonal quasicrystals in the Al-Cu-Co and Al-Ni-Co systems
Abstract
We report measurements of the specific heat C_p(T) and of the thermal conductivities λ^p(T) and λ^q(T) along the periodic direction and along a direction in the quasiperiodic plane, respectively, of single-grained samples of decagonal Al-Cu-Co and Al-Ni-Co at low temperatures. For both materials, the lattice contribution λ^p_ph(T) to the thermal conductivity along the periodic direction shows a maximum at ~ 20 K, characteristic of periodic crystals. The phonon thermal conductivity λ^q_ph(T) along a direction in the quasiperiodic plane is only weakly temperature-dependent between 30 and 70 K, in agreement with the concept of structural scattering of phonons in quasicrystals. The low linear-in-T term to C_p(T) of decagonal Al-Cu-Co and Al-Ni-Co of 0.51T and 0.63T ;mJ g-atom-1 K-1, respectively, indicates a low density of electronic states at E_F. The lattice contribution C_ph(T) to the low-temperature specific heat C_p(T) of the Al-Cu-Co and Al-Ni-Co quasicrystals is compatible with Debye temperatures ΘD of 596 and 562 K, respectively.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 1997
- Bibcode:
- 1997APS..MAR.K1814C