High-Temperature Specific Heat of Al–Cu–Ru Icosahedral Quasicrystals and 1/1 Crystal Approximants

Abstract

We report the results of specific heat measurements for Al–Cu–Ru icosahedral quasicrystals (i-QCs) and 1/1 crystal approximants (1/1-CAs) in the temperature range from 350 to 1250 K. The i-QCs and 1/1-CAs showed a marked upward deviation of the specific heat from the value of Dulong-Petit’s law above 600 K, reaching approximately 1.5 times the value at 1100 K. In addition, some i-QCs showed a large broad peak in the specific heat at approximately 1200 K. The origin of these excessive specific heat values above the Dulong-Petit value is discussed considering the high-dimensional nature of the structural order in the QCs and CAs.

Fig. 3 (a): Temperature dependence of specific heat per atom at constant pressure, c_P, for nine samples (four i-QCs, three 1/1-CAs, one MC, and one Cu sample). (b): Temperature dependence of specific heat per atom at constant volume, c_V, converted from c_P in (a).