Ultrasonic Velocity in Large-Grained Al–Li–Cu Quasicrystal

Abstract

Ultrasonic measurements have been made between 2 K and 200 K for quasicrystalline Al₆Li₄Cu. The temperature dependence of the ultrasonic velocity shows an anomalous decrease below 50 K with decreasing temperature. This anomaly is explained well by the existence of two-level systems without distribution of energy splittings.