Thermal activation processes and harmonic oscillator relaxation contribution to the sound velocity in neutron-irradiated quartz crystals

摘要

The behaviour of the sound velocity in glasses at low temperature above the maximum is not well understood. In this work, we report the measurements of the ultrasound velocity (270 MHz) in neutron-irradiated quartz samples with irradiation doses 1.2 x 10(19) and 2.6 x 10(19) n/cm(2) in a temperature range from 5 to 35 K. We found that the relative change of the sound velocity is due to harmonic oscillators relaxation contribution. (C) 2003 Elsevier Science B.V. All rights reserved. [References: 18]