Mechanical losses in low loss materials studied by Cryogenic Resonant Acoustic spectroscopy of bulk materials (CRA spectroscopy)

TL;DR

This study employs CRA spectroscopy to analyze mechanical losses in silicon and calcium fluoride across 5 to 300 K, focusing on phonon interactions and defects affecting loss mechanisms.

Contribution

It introduces a novel cryogenic resonant acoustic spectroscopy method for detailed analysis of mechanical losses in bulk materials at cryogenic temperatures.

Findings

Losses are influenced by phonon-phonon interactions.

Defect-induced losses vary with temperature.

CRA spectroscopy effectively characterizes low-temperature mechanical damping.

Abstract

Mechanical losses of crystalline silicon and calcium fluoride have been analyzed in the temperature range from 5 to 300 K by our novel mechanical spectroscopy method, cryogenic resonant acoustic spectroscopy of bulk materials (CRA spectrocopy). The focus lies on the interpretation of the measured data according to phonon-phonon interactions and defect induced losses in consideration of the excited mode shape.