%0 Journal Article
%T Investigation of mechanical losses of thin silicon flexures at low temperatures
%A R. Nawrodt
%A C. Schwarz
%A S. Kroker
%A I. W. Martin
%A F. Br¨¹ckner
%A L. Cunningham
%A V. Gro£¿e
%A A. Grib
%A D. Heinert
%A J. Hough
%A T. K£¿sebier
%A E. B. Kley
%A R. Neubert
%A S. Reid
%A S. Rowan
%A P. Seidel
%A M. Th¨¹rk
%A A. T¨¹nnermann
%J Physics
%D 2010
%I arXiv
%R 10.1088/0264-9381/30/11/115008
%X The investigation of the mechanical loss of different silicon flexures in a temperature region from 5 to 300 K is presented. The flexures have been prepared by different fabrication techniques. A lowest mechanical loss of $3\times10^{-8}$ was observed for a 130 $\mu$m thick flexure at around 10 K. While the mechanical loss follows the thermoelastic predictions down to 50 K a difference can be observed at lower temperatures for different surface treatments. This surface loss will be limiting for all applications using silicon based oscillators at low temperatures. The extraction of a surface loss parameter using different results from our measurements and other references is presented. We focused on structures that are relevant for gravitational wave detectors. The surface loss parameter $\alpha_s$ = 0.5 pm was obtained. This reveals that the surface loss of silicon is significantly lower than the surface loss of fused silica.
%U http://arxiv.org/abs/1003.2893v1