Low-temperature thermal properties of icosahedral Al-Re-Pd

We report measurements of the thermal conductivity lambda(T) and the specific heat C-p(T) of icosahedral Al70Re8.6Pd21.4 at low temperatures. Below 1 K, the behaviour of the quasilattice thermal conductivity lambda(ph)(T) is compatible with the scattering of vibrational excitations involving tunnelling states and grain boundaries. The specific heat C-p(T) contains a small linear contribution gamma T. Our lambda(ph)(T) results indicate that a substantial part of gamma T may be attributed to the excitations of tunnelling states. Below 0.4 K C-p(T) increases with decreasing T and at the lowest temperatures it varies as T-2, suggestive of an interaction of the quadrupolar moments of Re-185 and Re-187 nuclei with the gradient of electric fields induced by their neighbours.