Tag Archives: conductive diamond coated AFM probes

Insights into dynamic sliding contacts from conductive atomic force microscopy

Friction in nanoscale contacts is determined by the size and structure of the interface that is hidden between the contacting bodies. One approach to investigating the origins of friction is to measure electrical conductivity as a proxy for contact size and structure. However, the relationships between contact, friction and conductivity are not fully understood, limiting the usefulness of such measurements for interpreting dynamic sliding properties.*

In their study “Insights into dynamic sliding contacts from conductive atomic force microscopy” Nicholas Chan, Mohammad R. Vazirisereshk, Ashlie Martini and Philip Egberts used atomic force microscopy (AFM) to simultaneously acquire lattice resolution images of the lateral force and current flow through the tip–sample contact formed between a highly oriented pyrolytic graphite (HOPG) sample and a conductive diamond AFM probe to explore the underlying mechanisms and correlations between friction and conductivity. Both current and lateral force exhibited fluctuations corresponding to the periodicity of the HOPG lattice.

Unexpectedly, while lateral force increased during stick events of atomic stick-slip, the current decreased exponentially.*

The results presented in the study by Nicholas Chan et al. confirm that the correlation between conduction and atom–atom distance previously proposed for stationary contacts can be extended to sliding contacts in the stick-slip regime.*

A NANOSENSORS™ conductive diamond coated AFM probe CDT-CONTR was used to obtain all experimental data presented in their manuscript.*

Figure 1 (a) from “Insights into dynamic sliding contacts from conductive atomic force microscopy” by Nicholas Chan et al:
A schematic of the experimental setup is shown in Fig. 1(a). The experiment was conducted using an ultra-high vacuum (UHV) (RHK) AFM at room temperature at a pressure of <1109Torr. A doped diamond coated cantilever (NANOSENSORS CDT-CONTR) with a normal bending spring constant of 0.86 N m1and lateral spring constant of 10 N m1was used to obtain all experimental data presented in this manuscript.

Figure 1 (a) from “Insights into dynamic sliding contacts from conductive atomic force microscopy” by Nicholas Chan et al:
A schematic of the experimental setup is shown in Fig. 1(a). The experiment was conducted using an ultra-high vacuum (UHV)AFM at room temperature at a pressure of <1109Torr. A doped diamond coated cantilever (NANOSENSORS CDT-CONTR) with a normal bending spring constant of 0.86 N m1and lateral spring constant of 10 N m1was used to obtain all experimental data presented in this manuscript.

*Nicholas Chan, Mohammad R. Vazirisereshk, Ashlie Martini and Philip Egberts
Insights into dynamic sliding contacts from conductive atomic force microscopy
Nanoscale Advances., 2020, Advance Article
DOI: 10.1039/d0na00414f

Please follow this external link to read the whole article: https://pubs.rsc.org/en/content/articlepdf/2020/na/d0na00414f

Open Access: The article “Insights into dynamic sliding contacts from conductive atomic force microscopy” by Nicholas Chan, Mohammad R. Vazirisereshk, Ashlie Martini and Philip Egberts is licensed under a Creative Commons Attribution 3.0 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/3.0/.

Converse flexoelectricity yields large piezoresponse force microscopy signals in non-piezoelectric materials

NANOSENSORS™ conductive diamond coated  CDT-NCLR AFM probes were used for the piezoresponse force microscopy ( PFM ) on non-piezoelectric dielectrics described in this brand new publication: “Converse flexoelectricity yields large piezoresponse force microscopy signals in non-piezoelectric materials” by Amir Abdollahi et al.

The autors show theoretically and experimentally, that large effective piezoelectric coefficients can be measured in non-piezoelectric dielectrics due to converse flexoelectricity.*

Figure 4 from “Converse flexoelectricity yields large piezoresponse force microscopy signals in non-piezoelectric materials” by Amir Abdollahi et al.: Study of converse flexoelectricity induced at the tip apex of an atomic force microscope cantilever as a function of the applied force. a Effective piezoelectric coefficient as a function of applied force for the SrTiO3 crystal. Filled squares correspond to the values obtained after the simulation. Empty circles correspond to the experimental values obtained with a NANOSENSORS CDT-FM AFM tip with a cantilever of medium stiffness (k ≈ 2.8 Nm−1) coated with doped diamond. The error bars correspond to the error of the linear fitting of the experimental data, which correlates the measured electromechanical amplitude of oscillation Δh with the Vac applied voltage. b The effective contact radius a scales with the force, and is determined by the tip radius. The experimental tip radius is obtained after the measurement of the nanoscale electromechanical response from the scanning electron microscopy image of the used tip. In this case, the tip radius of the diamond coated tip is 105 nm, and is observed to keep a spherical shape after the measurements
Figure 4 from “Converse flexoelectricity yields large piezoresponse force microscopy signals in non-piezoelectric materials” by Amir Abdollahi et al.:
Study of converse flexoelectricity induced at the tip apex of an atomic force microscope cantilever as a function of the applied force. a Effective piezoelectric coefficient as a function of applied force for the SrTiO3 crystal. Filled squares correspond to the values obtained after the simulation. Empty circles correspond to the experimental values obtained with a Nanosensors CDT-FMR tip with a cantilever of medium stiffness (k ≈ 2.8 Nm−1) coated with doped diamond. The error bars correspond to the error of the linear fitting of the experimental data, which correlates the measured electromechanical amplitude of oscillation Δh with the Vac applied voltage. b The effective contact radius a scales with the force, and is determined by the tip radius. The experimental tip radius is obtained after the measurement of the nanoscale electromechanical response from the scanning electron microscopy image of the used tip. In this case, the tip radius of the diamond coated tip is 105 nm, and is observed to keep a spherical shape after the measurements

*Amir Abdollahi, Neus Domingo, Irene Arias, Gustau Catalan
Converse flexoelectricity yields large piezoresponse force microscopy signals in non-piezoelectric materials
Nature Communicationsvolume 10, Article number: 1266 (2019)
DOI: https://doi.org/10.1038/s41467-019-09266-y

Please refer to this external link for the full article: https://www.nature.com/articles/s41467-019-09266-y

Open Access The article «Converse flexoelectricity yields large piezoresponse force microscopy signals in non-piezoelectric materials» by Amir Abdollahi et al. 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/.