Frequency dependence of viscous and viscoelastic dissipation in coated micro-cantilevers from noise measurement

Pierdomenico Paolino (1) , Ludovic Bellon (1)

1 Phys-ENS - Laboratoire de Physique de l'ENS Lyon

We measure the mechanical thermal noise of soft silicon atomic force microscopy cantilevers. Using an interferometric setup, we have a resolution down to 1E-14 m/rtHz on a wide spectral range (3 Hz to 1E5 Hz). The low frequency behavior depends dramatically on the presence of a reflective coating: almost flat spectrums for uncoated cantilevers versus 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.

Keywords: Thermal noise; viscoelasticity; cantilever coating; fluctuation dissipation theorem; Sader model

Domains: Physics [physics]; Condensed Matter [cond-mat]; Materials Science [cond-mat.mtrl-sci]; Physics [physics]; Physics [physics]; General Physics [physics.gen-ph]; Physics [physics]; Physics [physics]; Instrumentation and Detectors [physics.ins-det]

Pierdomenico Paolino, Ludovic Bellon. Frequency dependence of viscous and viscoelastic dissipation in coated micro-cantilevers from noise measurement. Nanotechnology, 2009, 20 (20), pp.405705. ⟨10.1088/0957-4484/20/40/405705⟩. ⟨ensl-00362038v2⟩