Identification and Analysis of Artifacts in Amplitude Modulated Atomic Force Microscopy Array Operation

2017 ◽  
Vol 12 (5) ◽  
Author(s):  
Samuel Jackson ◽  
Stefanie Gutschmidt
Keyword(s):  
Atomic Force Microscopy ◽  
Separation Distance ◽  
Constant Frequency ◽  
Single Beam ◽  
Force Microscopy ◽  
Atomic Force ◽  
Close Proximity ◽  
Output Amplitude ◽  
Sample Separation ◽  
The Relationship

To increase measurement throughput of atomic force microscopy (AFM), multiple cantilevers can be placed in close proximity to form an array for parallel throughput. In this paper, we have measured the relationship between amplitude and tip-sample separation distance for an array of AFM cantilevers on a shared base actuated at a constant frequency and amplitude. The data show that discontinuous jumps in output amplitude occur within the response of individual beams. This is a phenomenon that does not occur for a standard, single beam system. To gain a better understanding of the coupled array response, a macroscale experiment and mathematical model are used to determine how parameter space alters the measured amplitude. The results demonstrate that a cusp catastrophe bifurcation occurs due to changes in individual beam resonant frequency, as well as significant zero-frequency coupling at the point of jump-to-contact. Both of these phenomena are shown to account for the amplitude jumps observed in the AFM array.

Influence of Excitation Conditions in Dual-Frequency Tapping-Mode Atomic Force Microscopy

2012 ◽  
Author(s):  
Andrew J. Dick ◽  
Wei Huang
Keyword(s):  
Atomic Force Microscopy ◽  
Phase Difference ◽  
Response Magnitude ◽  
Dual Frequency ◽  
Tapping Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Relationship ◽  
Excitation Conditions ◽  
Mode Atomic Force Microscopy

In this work, the influence of excitation conditions on the performance of a dual-frequency version of tapping-mode atomic force microscopy is studied. In the authors’ previous work, a relationship was identified between the interaction force regime(s) influencing the response of the probe and the specific spectral components observed to be significant in the response. Numerical studies are performed with a three-mode approximation of an atomic force microscope (AFM) probe. This study is conducted by modifying the excitation strength to vary the free response magnitude and the response magnitude ratio, by varying the phase difference between the two excitation components, and by exploring other frequencies for the secondary excitation component. This study reveals undesirable amplitude discontinuities when the influence of the secondary excitation component is too strong, conditions where the accuracy of the relationship is improved, how the selection of the excitation phase difference can influence the results, and the potential of alternative frequency combinations. Through an improved understanding of the relationship, it may provide the means to perform simultaneous imaging and characterization with improved performance using standard AFM systems and AFM probes.

Measurement of Frictional Forces in Atomic Force Microscopy

2007 ◽  
Vol 121-123 ◽  
pp. 851-854 ◽  
Author(s):  
D.H. Choi ◽  
W. Hwang
Keyword(s):  
Atomic Force Microscopy ◽  
Conversion Factor ◽  
Calibration Method ◽  
Adhesive Force ◽  
Torsional Angle ◽  
Force Microscopy ◽  
Atomic Force ◽  
Force Moment ◽  
Frictional Forces ◽  
The Relationship

A new calibration method of frictional forces in atomic force microscopy (AFM) is suggested. An angle conversion factor is defined using the relationship between torsional angle and frictional signal. When the factor is measured, the slopes of the torsional angle and the frictional signal as a function of the normal force are used to eliminate the effect of the adhesive force. Moment balance equations on the flat surface and the top edge of a commercial step grating are used to obtain the angle conversion factor. After the factor is obtained from an AFM system, it can be applied to all cantilevers without additional experiments.

scholarly journals Reinforcement Mechanism of Carbon Black-Filled Rubber Nanocomposite as Revealed by Atomic Force Microscopy Nanomechanics

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3922
Author(s):  
Xiaobin Liang ◽  
Makiko Ito ◽  
Ken Nakajima
Keyword(s):  
Atomic Force Microscopy ◽  
Stress Distribution ◽  
Carbon Black ◽  
Stress Concentrations ◽  
Force Microscopy ◽  
Reinforcement Mechanism ◽  
Atomic Force ◽  
Filled Rubber ◽  
First Time ◽  
The Relationship

In this study, atomic force microscopy (AFM) nanomechanics were used to visualize the nanoscale stress distribution in carbon black (CB)-reinforced isoprene rubber (IR) vulcanizates at different elongations and quantitatively evaluate their volume fractions for the first time. The stress concentrations in the protofibrous structure (stress chains) that formed around the CB filler in CB-reinforced IR vulcanizates were directly observed at the nanoscale. The relationship between the local nanoscale stress distribution and macroscopic tensile properties was revealed based on the microscopic stress distribution and microscopic spatial structure. This study can help us gain insight into the microscopic reinforcement mechanism of carbon black-containing rubber composites.

Utilization of a Two-Beam Cantilever Array for Enhanced Atomic Force Microscopy Sensitivity

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Samuel Jackson ◽  
Stefanie Gutschmidt
Keyword(s):  
Atomic Force Microscopy ◽  
Degrees Of Freedom ◽  
Sample Surface ◽  
Feedback Signal ◽  
Single Beam ◽  
Force Microscopy ◽  
Beam Array ◽  
Atomic Force ◽  
Alternative Approach ◽  
Cantilever Array

An array of cantilevers offers an alternative approach to standard single beam measurement in the context of atomic force microscopy (AFM). In comparison to a single beam, a multi-degrees-of-freedom system offers a greater level of flexibility with regard to parameter selection and tuning. By utilizing changes in the system eigenmodes as a feedback signal, it is possible to enhance the sensitivity of AFM to changes in sample topography above what is achievable with standard single beam techniques. In this paper, we analyze a two-beam array operated in FM-AFM mode. The array consists of a single active cantilever that is excited with a 90 deg phase-shifted signal and interacts with the sample surface. The active beam is mechanically coupled to a passive beam, which acts to vary the response between synchronized and unsynchronized behavior. We use a recently developed mathematical model of the coupled cantilever array subjected to nonlinear tip forces to simulate the response of the described system with different levels of coupling. We show that the sensitivity of the frequency feedback signal can be increased significantly in comparison to the frequency feedback from a single beam. This is a novel application for an AFM array that is not present in the literature.

scholarly journals Bimodal atomic force microscopy driving the higher eigenmode in frequency-modulation mode: Implementation, advantages, disadvantages and comparison to the open-loop case

2013 ◽  
Vol 4 ◽  
pp. 198-207 ◽  
Author(s):  
Daniel Ebeling ◽  
Santiago D Solares
Keyword(s):  
Atomic Force Microscopy ◽  
Frequency Modulation ◽  
Operation Mode ◽  
Excitation Amplitude ◽  
Open Loop ◽  
Constant Frequency ◽  
Force Microscopy ◽  
Advantages And Disadvantages ◽  
Atomic Force ◽  
Modulation Mode

We present an overview of the bimodal amplitude–frequency-modulation (AM-FM) imaging mode of atomic force microscopy (AFM), whereby the fundamental eigenmode is driven by using the amplitude-modulation technique (AM-AFM) while a higher eigenmode is driven by using either the constant-excitation or the constant-amplitude variant of the frequency-modulation (FM-AFM) technique. We also offer a comparison to the original bimodal AFM method, in which the higher eigenmode is driven with constant frequency and constant excitation amplitude. General as well as particular characteristics of the different driving schemes are highlighted from theoretical and experimental points of view, revealing the advantages and disadvantages of each. This study provides information and guidelines that can be useful in selecting the most appropriate operation mode to characterize different samples in the most efficient and reliable way.

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