Cryogenic resonant acoustic spectroscopy of bulk materials (CRA spectroscopy)

Abstract

The capability to measure Q factors at cryogenic temperatures enhances the ability to study relaxation processes in solids. Here we present a high-precision cryogenic setup with the ability to measure Q factors of at least 10(9). This level of sensitivity offers new potential for analyzing relaxation processes in solids and for correlating mode shape and relaxation strength. Our improved method of mechanical spectroscopy, cryogenic resonant acoustic spectroscopy of bulk materials, is verified by identifying relaxation processes in low-loss quartz crystals. For the first time, we observe additional damping peaks. The mechanical Q factors of different modes of cylindrical crystalline quartz substrates were measured from 300 down to 6 K. Resonant modes with frequencies between 10 and 325 kHz were excited without contact to the substrates and the ring down of the amplitudes was recorded using an interferometric vibration readout.

Comparison of the temperature dependence of the mechanical dissipation in thin films of Ta 2 O 5 and Ta 2 O 5 doped with TiO 2

“…In Figures 1 to 5 it can be seen that the peak in the undoped coating is narrower than the peak observed in the coating doped with TiO 2 and it is clear from a fit to a Debye peak [20] that the loss peak in the undoped coating occurs at slightly lower temperatures. No significant change in the temperature of the loss peak was observed when the sample was re-clamped.…”

Mechanical losses in low loss materials studied by cryogenic resonant acoustic spectroscopy of bulk materials (CRA spectroscopy)

“…Therefore, our novel mechanical spectroscopy method, cryogenic resonant acoustic spectroscopy of bulk materials (CRA spectrocopy), was applied in the temperature range from 5 to 300 K. Instead of the small losses in the detection band, the reciprocals of the losses at the resonant frequencies, the mechanical quality factors Q, have been measured. Following the test of our method on the fairly well-known material crystalline quartz [3], results on silicon and calcium fluoride are presented. For details on the measuring set-up and method see references [4] and [5].…”

High-sensitivity tool for studying phonon related mechanical losses in low loss materials

“…For this purpose the tungsten wire is polished with diamond paste and afterwards cleaned with isopropanol. Experiments show, that the location of the wire on [2]. b) Schematic view of the suspension system.…”

“…Intrinsic loss processes in pure materials are best examined by using bulk materials. A novel method of mechanical spectrocopy on bulk materials, cryogenic resonant acoustic spectroscopy of bulk materials (CRA spectroscopy), has been successfully tested on the fairly well-known material crystalline quartz [2]. A further characterization of the method with focus on the suspension system is presented in this paper.…”