Tag Archives: materials science

Temperature effects on the nano-friction across exposed atomic step edges

In the article “Temperature effects on the nano-friction across exposed atomic step edges” Wen Wang, Ashu Wang and Lingyan Zeng describe how they used friction force microscopy ( FFM ) under ultrahigh vacuum ( UHV) conditions to study the temperature dependence of nanoscale friction between a silicon AFM tip ( NANOSENSORS™ PointProbe® Plus PPP-LFMR AFM probe for lateral/friction force microscopy ) and a freshly cleaved HOPG surface with exposed single- and double-layer step edges.*

They present experimental measurements as well as theoretical calculations of the temperature effects on atomic friction across HOPG surface step edges.*

Among other things the authors found that the resistive force for the double-layer step edge was twice as large as that of the single-step edge, and simultaneously, the assistive force that resulted from the horizontal component of the total force acting on the AFM tip seemed to be less influenced by the height of the step edges.*

Their experimental results also showed that temperature had very little effect on the friction coefficients at the step edges, which is inconsistent with the thermal activated friction where friction should decrease with temperature.*

Based on the theoretical studies, this observation can be explained by a process where the temperature effect is very small compared with the edge Schwoebel–Ehrlich barrier.*

The authors hope that their findings will contribute to understanding the temperature effects on macroscopic friction having a lot of step edges at the interface.*

Figure 1 from “Temperature effects on the nano-friction across exposed atomic step edges” by Wen Wang et al.:
 Experimental setup and the topographic image of the HOPG surface with step edges used in our measurements. (a) Illustration of the experimental setup. All experiments have been performed using a conventional friction force microscope on a freshly cleaved HOPG sample which was in contact with the temperature control stage under UHV conditions. (b) The typical topographic image of the HOPG surface with a single- and double-layer step edge obtained at T = 297.7 K using the contact mode operation with an applied normal force of 13.1 nN and a scan velocity of 1.25 μm/s. (c) The cross-section height profile across the step edges highlighted in (b). The black arrows in (b) and (c) indicate the scanning direction.  NANOSENSORS PointProbe Plus PPP-LFMR AFM probes for lateral force microscopy and friction force microscopy were used.
Figure 1 from “Temperature effects on the nano-friction across exposed atomic step edges” by Wen Wang et al.:
 Experimental setup and the topographic image of the HOPG surface with step edges used in our measurements. (a) Illustration of the experimental setup. All experiments have been performed using a conventional friction force microscope on a freshly cleaved HOPG sample which was in contact with the temperature control stage under UHV conditions. (b) The typical topographic image of the HOPG surface with a single- and double-layer step edge obtained at T = 297.7 K using the contact mode operation with an applied normal force of 13.1 nN and a scan velocity of 1.25 μm/s. (c) The cross-section height profile across the step edges highlighted in (b). The black arrows in (b) and (c) indicate the scanning direction.

*Wen Wang, Ashu Wang and Lingyan Zeng
Temperature effects on the nano-friction across exposed atomic step edges
AIP Advances 10, 085322 (2020)
DOI: https://doi.org/10.1063/5.0019196

Please follow this external link to read the full article: https://aip.scitation.org/doi/10.1063/5.0019196

Open Access The article “Temperature effects on the nano-friction across exposed atomic step edges” by Wen Wang, Ashu Wang and Lingyan Zeng is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Signal Origin of Electrochemical Strain Microscopy and Link to Local Chemical Distribution in Solid State Electrolytes

Solid state electrolytes (SSEs) are interesting materials that could potentially replace the currently used organic electrolytes in lithium‐ion batteries (LIBs). *

Electrochemical strain microscopy (ESM), a research technique based on atomic force microscopy (AFM), was developed to locally probe ion movement in electrodes based on electro-chemo-mechanical coupling measure through the AFM cantilever deflection. It can be used to characterize Li-ion mobility in energy materials with extremely high spatial resolution. *

The main challenge with ESM is its nonquantitative nature due to complex AFM cantilever dynamics in contact mode when performed on resonance as well as signal contribution that are not necessarily related to ions such as electrostatic forces.*

In the article “ Signal Origin of Electrochemical Strain Microscopy and Link to Local Chemical Distribution in Solid State Electrolytes “ Nino Schön, Roland Schierholz, Stephen Jesse, Shicheng Yu, Rüdiger‐A. Eichel, Nina Balke and Florian Hausen investigate the exact signal formation process of electrochemical strain microscopy (ESM) when it is applied on sodium super ionic conductor (NASCIO)-type solid state electrolytes containing Na- and Li-ions.*

In their research the authors correlatively use various scanning probe microscopy (SPM) based microscopy techniques together with scanning electron microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy ( EDX ) at identical positions of the solid state electrolyte LATP.*

They find that changes in the dielectric properties are responsible for the detected contrast in the deflection of the AFM cantilever instead of a physical volume change as a result of Vegard’s Law. The AFM cantilever response is strongly reduced in areas of high sodium content which is attributed to a reduction of the AFM tip-sample capacitance in comparison with areas with high lithium content.*

This is the first time a direct link between electrostatic forces in contact mode and local chemical information is demonstrated on SSEs. The results presented in the article open up the possibility to learn more since dielectric properties are sensitive to subtle changes in local chemical composition.*

NANOSENSORS conductive Platinum-Iridium coated PointProbe® Plus PPP-EFM AFM probes were primarily used in the research for this article.

Figure 1 from Nino Schön et al. «Signal Origin of Electrochemical Strain Microscopy and Link to Local Chemical Distribution in Solid State Electrolytes”:
a) Topography, b) deflection error, and c) corresponding cantilever deflection change (Dac) map of a 30 µm × 30 µm area of LATP. d) Noncontact EFM amplitude map in the same area.
NANOSENSORS conductive platinum-iridium coated PointProbe Plus PPP-EFM AFM probes were used.
Figure 1 from Nino Schön et al. «Signal Origin of Electrochemical Strain Microscopy and Link to Local Chemical Distribution in Solid State Electrolytes”:
a) Topography, b) deflection error, and c) corresponding cantilever deflection change (Dac) map of a 30 µm × 30 µm area of LATP. d) Noncontact EFM amplitude map in the same area.

*Nino Schön, Roland Schierholz, Stephen Jesse, Shicheng Yu, Rüdiger‐A. Eichel, Nina Balke, Florian Hausen
Signal Origin of Electrochemical Strain Microscopy and Link to Local Chemical Distribution in Solid State Electrolytes
Small Methods, Early View, Online Version of Record before inclusion in an issue 2001279
DOI: https://doi.org/10.1002/smtd.202001279

Please follow this external link to read the full article: https://onlinelibrary.wiley.com/doi/10.1002/smtd.202001279

Open Access The article “Signal Origin of Electrochemical Strain Microscopy and Link to Local Chemical Distribution in Solid State Electrolytes” by Nino Schön, Roland Schierholz, Stephen Jesse, Shicheng Yu, Rüdiger‐A. Eichel, Nina Balke, Florian Hausen is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

In‐situ force measurement during nano‐indentation combined with Laue microdiffraction

A NANOSENSORS™ self-sensing self-activating Akiyama probe was used in a home-built Scanning Probe Microscope for this interesting research article.

*Florian Lauraux, Sarah Yehya, Stéphane Labat, Jean‐Sébastien Micha, Odile Robach, Oleg Kovalenko, Eugen Rabkin, Olivier Thomas, Thomas W. Cornelius
In‐situ force measurement during nano‐indentation combined with Laue microdiffraction
Nano Select , Volume2, Issue1, January 2021, Pages 99-106
DOI: https://doi.org/10.1002/nano.202000073

NANOSENSORS self-sensing and self-actuating Akiyama-probe AFM probe
NANOSENSORS self-sensing and self-actuating Akiyama-probe

Please have a look at the abstract below or follow the external link above to read the full article.

Abstract:

“For the characterization of the mechanical properties of materials the precise measurements of stress‐strain curves is indispensable. In situ nano‐mechanical testing setups, however, may lack the precision either in terms of strain or stress determination. Recently, the custom‐built scanning force microscope SFINX was developed which is compatible with third‐generation synchrotron end‐stations allowing for in situ nano‐mechanical tests in combination with nanofocused synchrotron x‐ray diffraction that is highly sensitive to strain and defects. The usage of a self‐actuating and self‐sensing cantilever tremendously increases the compactness of the system but lacks deflection sensitivity and, thus the force measurement. This deficiency is resolved by in situ monitoring the diffraction peaks of the Si cantilever by Laue microdiffraction during the nano‐indentation of a gold crystal. The orientation and, hence, the deflection of the Si cantilever is deduced from the displacement of the Si Laue spots on the detector giving force accuracies of better than 90 nN. At the same time, the dislocation density in the indented Au crystal is tracked by monitoring the Au Laue spots eventually resulting in complete stress‐dislocation density curves.”*

Open Access: The article “In‐situ force measurement during nano‐indentation combined with Laue microdiffraction” by Florian Lauraux, Sarah Yehya, Stéphane Labat, Jean‐Sébastien Micha, Odile Robach, Oleg Kovalenko, Eugen Rabkin, Olivier Thomas, Thomas W. Cornelius is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.