scholarly journals Challenges and complexities of multifrequency atomic force microscopy in liquid environments

2014 ◽  
Vol 5 ◽  
pp. 298-307 ◽  
Author(s):  
Santiago D Solares
Keyword(s):  
Atomic Force Microscopy ◽  
Frequency Modulation ◽  
Open Loop ◽  
Phase Relaxation ◽  
Specific Context ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging ◽  
Modulation Methods ◽  
Amplitude And Frequency Modulation

This paper illustrates through numerical simulation the complexities encountered in high-damping AFM imaging, as in liquid enviroments, within the specific context of multifrequency atomic force microscopy (AFM). The focus is primarily on (i) the amplitude and phase relaxation of driven higher eigenmodes between successive tip–sample impacts, (ii) the momentary excitation of non-driven higher eigenmodes and (iii) base excitation artifacts. The results and discussion are mostly applicable to the cases where higher eigenmodes are driven in open loop and frequency modulation within bimodal schemes, but some concepts are also applicable to other types of multifrequency operations and to single-eigenmode amplitude and frequency modulation methods.

Multi-Frequency Atomic Force Microscopy Combining Amplitude- and Frequency-Modulation Techniques

2012 ◽  
Vol 1422 ◽  
Author(s):  
Santiago D. Solares ◽  
Gaurav Chawla
Keyword(s):  
Atomic Force Microscopy ◽  
Frequency Modulation ◽  
Complementary Information ◽  
Control Loops ◽  
Force Microscopy ◽  
Atomic Force ◽  
Mode Of Operation ◽  
Modulation Techniques ◽  
Different Response ◽  
Amplitude And Frequency Modulation

ABSTRACTMulti-frequency atomic force microscopy (AFM) offers additional response signals in comparison to traditional dynamic AFM. Furthermore, depending on the mode of operation used, the higher eigenmode responses are generally not directly influenced by the topographical acquisition control loops, such that they can explore a fuller range of tip-sample interactions. In this work we describe the implementation of multi-frequency imaging schemes that enable the acquisition of topographical, phase and frequency shift contrast in tapping-mode operation. This type of characterization can be especially useful for soft, highly dissipative samples, such as polymers, for which the various response channels can exhibit significantly different response, thus providing complementary information. We discuss typical results obtained as well as important challenges that need to be addressed in order to develop a fully quantitative technique.

scholarly journals Quantitative comparison of wideband low-latency phase-locked loop circuit designs for high-speed frequency modulation atomic force microscopy

2018 ◽  
Vol 9 ◽  
pp. 1844-1855 ◽  
Author(s):  
Kazuki Miyata ◽  
Takeshi Fukuma
Keyword(s):  
Atomic Force Microscopy ◽  
Frequency Modulation ◽  
High Speed ◽  
Feedback Loop ◽  
Response Speed ◽  
Low Latency ◽  
Pass Filter ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging

A phase-locked loop (PLL) circuit is the central component of frequency modulation atomic force microscopy (FM-AFM). However, its response speed is often insufficient, and limits the FM-AFM imaging speed. To overcome this issue, we propose a PLL design that enables high-speed FM-AFM. We discuss the main problems with the conventional PLL design and their possible solutions. In the conventional design, a low-pass filter with relatively high latency is used in the phase feedback loop, leading to a slow response of the PLL. In the proposed design, a phase detector with a low-latency high-pass filter is located outside the phase feedback loop, while a subtraction-based phase comparator with negligible latency is located inside the loop. This design minimizes the latency within the phase feedback loop and significantly improves the PLL response speed. In addition, we implemented PLLs with the conventional and proposed designs in the same field programmable gate array chip and quantitatively compared their performances. The results demonstrate that the performance of the proposed PLL is superior to that of the conventional PLL: 165 kHz bandwidth and 3.2 μs latency in water. Using this setup, we performed FM-AFM imaging of calcite dissolution in water at 0.5 s/frame with true atomic resolution. The high-speed and high-resolution imaging capabilities of the proposed design will enable a wide range of studies to be conducted on various atomic-scale dynamic phenomena at solid–liquid interfaces.

scholarly journals Spatial horizons in amplitude and frequency modulation atomic force microscopy

Nanoscale ◽  
2012 ◽  
Vol 4 (7) ◽  
pp. 2463 ◽  
Author(s):  
Josep Font ◽  
Sergio Santos ◽  
Victor Barcons ◽  
Neil H. Thomson ◽  
Albert Verdaguer ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Frequency Modulation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Amplitude And Frequency Modulation

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.

Brittle Behaviour in Aspirin Crystals: Evidence of Spalling Fracture

2020 ◽  
Author(s):  
Benjamin P. A. Gabriele ◽  
Craig J. Williams ◽  
Douglas Stauffer ◽  
Brian Derby ◽  
Aurora J. Cruz-Cabeza
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Single Crystals ◽  
Spalling Fracture ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging

<div> <div> <div> <p>Single crystals of aspirin form I were cleaved and indented on their dominant face. Upon inspection, it was possible to observe strongly anisotropic shallow lateral cracks due to the extreme low surface roughness after cleavage. Atomic Force Microscopy (AFM) imaging showed spalling fractures nucleating from the indent corners, forming terraces with a height of one or two interplanar spacings d100. The formation of such spalling fractures in aspirin was rationalised using basic calculations of attachment energies, showing how (100) layers are poorly bonded when compared to their relatively higher intralayer bonding. An attempt at explaining the preferential propagation of these fractures along the [010] direction is discussed. </p> </div> </div> </div>

Brittle Behaviour in Aspirin Crystals: Evidence of Spalling Fracture

2020 ◽  
Author(s):  
Benjamin P. A. Gabriele ◽  
Craig J. Williams ◽  
Douglas Stauffer ◽  
Brian Derby ◽  
Aurora J. Cruz-Cabeza
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Single Crystals ◽  
Spalling Fracture ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging

<div> <div> <div> <p>Single crystals of aspirin form I were cleaved and indented on their dominant face. Upon inspection, it was possible to observe strongly anisotropic shallow lateral cracks due to the extreme low surface roughness after cleavage. Atomic Force Microscopy (AFM) imaging showed spalling fractures nucleating from the indent corners, forming terraces with a height of one or two interplanar spacings d100. The formation of such spalling fractures in aspirin was rationalised using basic calculations of attachment energies, showing how (100) layers are poorly bonded when compared to their relatively higher intralayer bonding. An attempt at explaining the preferential propagation of these fractures along the [010] direction is discussed. </p> </div> </div> </div>

scholarly journals Atomic force microscopy analysis of native infectious and inactivated SARS-CoV-2 virions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sébastien Lyonnais ◽  
Mathilde Hénaut ◽  
Aymeric Neyret ◽  
Peggy Merida ◽  
Chantal Cazevieille ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Native Conformation ◽  
Force Microscopy ◽  
Enveloped Virus ◽  
Atomic Force ◽  
Afm Imaging ◽  
Level 3 ◽  
Microscopy Analysis ◽  
Virus Morphology ◽  
Nanoscale Level

AbstractSARS-CoV-2 is an enveloped virus responsible for the Coronavirus Disease 2019 (COVID-19) pandemic. Here, single viruses were analyzed by atomic force microscopy (AFM) operating directly in a level 3 biosafety (BSL3) facility, which appeared as a fast and powerful method to assess at the nanoscale level and in 3D infectious virus morphology in its native conformation, or upon inactivation treatments. AFM imaging reveals structurally intact infectious and inactivated SARS-CoV-2 upon low concentration of formaldehyde treatment. This protocol combining AFM and plaque assays allows the preparation of intact inactivated SARS-CoV-2 particles for safe use of samples out of level 3 laboratory to accelerate researches against the COVID-19 pandemic. Overall, we illustrate how adapted BSL3-AFM is a remarkable toolbox for rapid and direct virus analysis based on nanoscale morphology.

Atomic force microscopy (AFM) imaging suggests that stromal interaction molecule 1 (STIM1) binds to Orai1 with sixfold symmetry

FEBS Letters ◽  
2014 ◽  
Vol 588 (17) ◽  
pp. 2874-2880 ◽  
Author(s):  
Dilshan Balasuriya ◽  
Shyam Srivats ◽  
Ruth D. Murrell-Lagnado ◽  
J. Michael Edwardson
Keyword(s):  
Atomic Force Microscopy ◽  
Force Microscopy ◽  
Stromal Interaction Molecule 1 ◽  
Atomic Force ◽  
Afm Imaging ◽  
Sixfold Symmetry
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