Frequency dependence of viscous and viscoelastic dissipation in coated micro-cantilevers from noise measurement.
We measure the mechanical thermal noise of soft silicon atomic force microscope cantilevers. Using an interferometric setup, we obtain a resolution down to 10(-14) m Hz(-1/2) on a wide spectral range (3-10(5) Hz). The low frequency behavior depends dramatically on the presence of a reflective coating: almost flat spectra for uncoated cantilevers versus a 1/f like trend for coated ones. The addition of a viscoelastic term in models of the mechanical system can account for this observation. Use of Kramers-Kronig relations validate this approach with a complete determination of the response of the cantilever: a power law with a small coefficient is found for the frequency dependence of viscoelasticity due to the coating, whereas the viscous damping due to the surrounding atmosphere is accurately described by the Sader model.
Paolino
P
P
Laboratoire de Physique, Ecole Normale Supérieure de Lyon, CNRS UMR5672, Université de Lyon, 46 Allée d'Italie, 69364 Lyon Cedex 07, France.
Bellon
L
L
D004548:Elasticity; D018625:Microscopy, Atomic Force / Q000379:methods*; D008962:Models, Theoretical; D036103:Nanotechnology / Q000379:methods; D014783:Viscosity