Ultrasound velocity in neutron‐irradiated quartz crystals above 5 K

Abstract

A linear temperature dependence of the sound velocity above 5 K is a universal property for amorphous and disordered solids. However, there are several theoretical models, which propose the explaination of this universal behaviour at intermediate temperatures. Previous low-temperature measurements have shown that the neutron-irradiated quartz can be used for the study of the glassy dynamics. In this paper we present the results of the ultrasound velocity measurements in neutron-irradiated quartz crystals at temperatures 5 -35 K and discuss them in the framework of the different models.Introduction Thermal and acoustical properties of amorphous solids below 1 K are well described in the framework of the tunnelling model [1,2,3]. Sound velocity of amorphous solids first increases logarithmically with temperature, reaches the maximum, and than decreases also logarithmically. This temperature dependence is described by equations: (∆v/v) res,TLS = C ln(T /T 0 ) and (∆v/v) rel,TLS = −

Impact of thermal frequency drift on highest precision force microscopy using quartz-based force sensors at low temperatures

“…This is much higher than expected from the change in v s or , as discussed above. From neutron irradiation it is known, that the change of v s with T depends strongly on the quality of the crystal, the rate of change increases linearly with the defect density [ 24 – 25 28 ]. Because the quartz resonators studied in this work are not from the same wafer and manufacturer, one might argue that the differences in ∂ ε/ ∂T can be caused by different crystal quality and material processing.…”