Simulations of switching vibrating cantilever in atomic force microscopy

2015

Ultramicroscopy

Keywords:Atomic force microscope High-speed dynamic AFM Fast actuation Q-controlled eigenmode of a cantilever a b s t r a c tWe present a high-speed operating method with feedback to be used in dynamic atomic force microscope (AFM) systems. In this method we do not use an actuator that has to be employed to move the tip or the sample as in conventional AFM setups. Instead, we utilize a Q-controlled eigenmode of an AFM cantilever to perform the function of the actuator. Simulations show that even with an ordinary tappingmode cantilever, imaging speed can be increased by about 2 orders of magnitude compared to conventional dynamic AFM imaging.

Section: Simulation Resultsmentioning

confidence: 86%

High-speed dynamic atomic force microscopy by using a Q-controlled cantilever eigenmode as an actuator

2015

Ultramicroscopy

“…The details of the simulation setup can be found elsewhere. 30 The simulations are done in a time domain with a step size of one thousandth of one period. To make sure that the steady state is reached, 10Q oscillation cycles are simulated.…”

Section: Simulations Of a New Harmonic Enhancement Methodsmentioning

confidence: 99%

“…͑A5͒ f 1 causes an amplitude damping 30 and can be related to oscillation amplitude and cantilever parameters under the assumption of low harmonic distortion as follows:…”

Section: Appendix: Analytical Approximation For Low Harmonic Distortionmentioning

confidence: 99%

Enhancing higher harmonics of a tapping cantilever by excitation at a submultiple of its resonance frequency

Atalar

2005

Phys. Rev. B

Cataloged from PDF version of article.In a tapping-mode atomic force microscope, the frequency spectrum of the oscillating cantilever contains higher harmonics at integer multiples of the excitation frequency. When the cantilever oscillates at its fundamental resonance frequency w(1), the high Q-factor damps the amplitudes of the higher harmonics to negligible levels, unless the higher flexural eigenmodes are coincident with those harmonics. One can enhance the nth harmonic by the Q factor when the cantilever is excited at a submultiple of its resonance frequency (w(1)/n). Hence, the magnitude of the nth harmonic can be measured easily and it can be utilized to examine the material properties. We show theoretically that the amplitude of enhanced higher harmonic increases monotonically for a range of sample stiffness, if the interaction is dominated by elastic force

“…Since the cantilever is excited below the resonance, its amplitude can increase if the fundamental component of the tip-sample force is in phase with the tip oscillation. 14,15 This situation can also be interpreted by using the linearized model of Martin et al 2 as a decrease in the cantilever spring constant due to positive force gradient. The third-harmonic amplitude A 3 is approximately 0.12 nm, on the average.…”

mentioning

confidence: 98%

Enhanced higher-harmonic imaging in tapping-mode atomic force microscopy

Applied Physics Letters

Atalar

2005

Cataloged from PDF version of article.Higher-harmonics generation in a tapping-mode atomic force microscope is a consequence of the nonlinear tip-sample interaction force. The higher harmonics contain important information about the materials’ nanomechanical properties. These harmonics can be significantly enhanced by driving the cantilever close to a submultiple of its resonant frequency. We present the results of enhanced higher-harmonic imaging experiments on several samples. The results indicate that enhanced higher harmonics can be utilized effectively for both material characterization and surface roughness analysis with a high signal-to-noise ratio.\ud © 2005 American Institute of Physic