Dissipation of micro-cantilevers as a function of air pressure and metallic coating
Université de Lyon, Laboratoire de physique, ENS Lyon, CNRS - 46 Allée d'Italie, Lyon 69364, France, EU
2 Department of Physics, East China Normal University - 3663 Zhongshan North Rd., Shanghai 200062, China
Accepted: 9 March 2012
In this letter, we characterize the internal dissipation of coated micro-cantilevers through their mechanical thermal noise. Using a home-made interferometric setup, we achieve a resolution down to in the measurement of their deflection. With the use of the fluctuation dissipation theorem and of the Kramers-Kronig relations, we rebuild the full mechanical response function from the measured noise spectrum, and investigate frequency-dependent dissipation as a function of the air pressure and of the nature of the metallic coatings. Using different thicknesses of gold coatings, we demonstrate that the internal viscoelastic damping is solely due to the dissipation in the bulk of the coating.
PACS: 46.35.+z – Viscoelasticity, plasticity, viscoplasticity / 05.40.Jc – Brownian motion / 07.10.Cm – Micromechanical devices and systems
© EPLA, 2012