Internal friction of vitreous silica measured with a double paddle oscillator

Abstract

A double-paddle oscillator was used to measure the internal friction of vitreous silica at very low temperatures. The advantages of this experimental technique are the low background loss and the possibility to perform measurements at different eigenmodes of the oscillator. Below 30 mK the internal friction was found to vary as T α . Surprisingly, the exponent α increases monotonically with frequency and varies between 0.85 at 0.33 kHz and 1.74 at 5 kHz.