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Beilstein J Nanotechnol. 2012; 3: 336–344.
Published online 2012 April 18. doi:  10.3762/bjnano.3.38
PMCID: PMC3343270

Drive-amplitude-modulation atomic force microscopy: From vacuum to liquids

Udo D Schwarz, Guest Editor

Summary

We introduce drive-amplitude-modulation atomic force microscopy as a dynamic mode with outstanding performance in all environments from vacuum to liquids. As with frequency modulation, the new mode follows a feedback scheme with two nested loops: The first keeps the cantilever oscillation amplitude constant by regulating the driving force, and the second uses the driving force as the feedback variable for topography. Additionally, a phase-locked loop can be used as a parallel feedback allowing separation of the conservative and nonconservative interactions. We describe the basis of this mode and present some examples of its performance in three different environments. Drive-amplutide modulation is a very stable, intuitive and easy to use mode that is free of the feedback instability associated with the noncontact-to-contact transition that occurs in the frequency-modulation mode.

Keywords: atomic force microscopy, control systems, dissipation, frequency modulation, noncontact

Abstract

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Articles from Beilstein Journal of Nanotechnology are provided here courtesy of Beilstein-Institut