Tag Archives: magnetic AC mode

From Polymer to Magnetic Porous Carbon Spheres: Combined Microscopy, Spectroscopy, and Porosity Studies

In their research paper “From Polymer to Magnetic Porous Carbon Spheres: Combined Microscopy, Spectroscopy, and Porosity Studies” Federico Cesano, Sara Cravanzola, Valentina Brunella, Alessandro Damin and Domenica Scarano, after having first reported the preparation of polymer waste-derived microporous carbon microspheres (SBET ~800 m2/g) 100–300 μm in size, investigate the morphology, porous texture and the surface properties of carbon and of magnetic carbon microspheres by multiple techniques.*

The multi-technique methodology they used aims at an extensive description of the different characteristics of activated carbons with magnetic properties.

For the Atomic Force Microscopy described in this paper NANOSENSORS™ SSS-MFMR AFM probes for high resolution magnetic force imaging were used for the topography images as well as the MFM imaging.

Figure 7 from “From Polymer to Magnetic Porous Carbon Spheres: Combined Microscopy, Spectroscopy, and Porosity Studies” by F. Cesano et al:
Three images described from left to right of Fe3O4-based carbon microspheres: first image on the left (a) AFM topography, middle image (b) the related phase signal, and the image on the right (c) MFM phase shift images at H = 60 nm lift height obtained in a second scan. The phase shift range in (c) is ~ 0.6 m°.
Figure 7 from “From Polymer to Magnetic Porous Carbon Spheres: Combined Microscopy, Spectroscopy, and Porosity Studies” by F. Cesano et al:
Fe3O4-based carbon microspheres: (a) AFM topography, (b) the related phase signal, and (c) MFM phase shift images at H = 60 nm lift height obtained in a second scan. The phase shift range in (c) is ~ 0.6 m°. e description

*Federico Cesano, Sara Cravanzola, Valentina Brunella, Alessandro Damin and Domenica Scarano
From Polymer to Magnetic Porous Carbon Spheres: Combined Microscopy, Spectroscopy, and Porosity Studies
Frontiers in Materials 6:84 (2019)
DOI: https://doi.org/10.3389/fmats.2019.00084

Please follow this external link to read the full research article: https://www.frontiersin.org/articles/10.3389/fmats.2019.00084/full

Open Access: The article « From Polymer to Magnetic Porous Carbon Spheres: Combined Microscopy, Spectroscopy, and Porosity Studies” by Federico Cesano, Sara Cravanzola, Valentina Brunella, Alessandro Damin and Domenica Scarano which is cited above 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/.

Observing single magnetite nanoparticles with a diameter of 10nm by using NANOSENSORS SSS-MFMR AFM probes

In their publication “Understanding electrostatic and magnetic forces in magnetic force microscopy: towards single supermagnetic nanoparticle resolution” Alexander Krivcov, Tanja Junkers and Hildegard Möbius describe methods to suppress capacitive coupling effects in MFM hiding the magnetic signal of magnetic nanoparticles.

During MFM measurements performed in an interleave mode moving the tip at a certain distance to the sample surface the tip is exposed not only to magnetic forces but to electrostatic forces between tip and substrates. In case of analyzing nanoparticles laying on a flat substrate, the electrostatic forces changes noticeably with increasing tip to substrate distance whenever the tip is retracted over a nanoparticle. This capacitive signal may overwhelm the magnetic signal that should be detected instead.

The authors propose several approaches to reduce these capacitive signals. The change in electrostatic forces could be minimized by avoiding retraction of tip over the nanoparticle. Therefore, it is proposed to use interleave linear mode following a linear approximation of the sample surface instead of the interleave lift mode following the sample surface as measured. By that, changes in distance between sample substrate and tip at the nanoparticles are avoided. Moreover, they propose using a substrate with a work function comparable to that of the tip in order to reduce electrostatic forces, in general. By applying an appropriate tip bias remaining electrostatic forces could compensated and further suppressed. Finally, the authors suggest using a tip that is as sharp as possible for decreasing the area of the capacitor and NANOSENSORS SSS-MFMR probes are the best choice for this.

The impact of the above mentioned optimizations have been validated experimentally by the authors. Finally, it turned out that if using super sharp magnetic tips further methods suppressing capacitive effects were not necessary. The authors were able to detect superparamagnetic nanoparticles at the single particle level on copper substrate with a NANOSENSORS SSS-MFMR probe without using additional parameters as e. g. tip bias or external magnetic field.Figure 12 from: A. Krivcov et. al, Understanding electrostatic and magnetic forces in magnetic force microscopy: towards single supermagnetic nanoparticle resolution: Figure 12. (a) topography of copper substrate with single magnetite nanoparticle; (b) phase image in 11 nm lift height with an attraction at the place of the nanoparticle; (c) Cross section of a single magnetite nanoparticle (dotted line in (a)) with 10 nm diameter taken on copper substrate with NANOSENSORS SSS-MFMR AFM probe

Figure 12  from: A. Krivcov et. al, Understanding electrostatic and magnetic forces in magnetic force microscopy: towards single supermagnetic nanoparticle resolution: Figure 12. (a) topography of copper substrate with single magnetite nanoparticle; (b) phase image in 11 nm lift height with an attraction at the place of the nanoparticle; (c) Cross section of a single magnetite nanoparticle (dotted line in (a)) with 10 nm diameter taken on copper substrate with SSS-MFMR tip

A. Krivcov, T. Junkers, and H. Möbius
Understanding electrostatic and magnetic forces in magnetic force microscopy: towards single superparamagnetic nanoparticle resolution
J. Phys. Commun., vol. 2, no. 7, p. 075019, 2018
DOI: https://doi.org/10.1088/2399-6528/aad3a4

The article “Understanding electrostatic and magnetic forces in magnetic force microscopy: towards single superparamagnetic nanoparticle resolution” by A. Krivcov, T. Junkers, and H. Möbius is licensed under the Creative Commons Attribution 3.0 License. To view a copy of this license, visit http://creativecommons.org/licenses/by/3.0.

MAC Mode Cantilevers for Keysight, Agilent and Molecular Imaging AFMs now available from NANOSENSORS

Do you have a Keysight, Agilent or Molecular Imaging Atomic Force Microscope in your lab? Are you using MAC Mode (Keysight Technologies’ patented magnetic AC mode ) to image soft samples or for imaging in fluids?
Then NANOSENSORS™ has the right cantilevers for you.

MAC mode imaging of lambda phage DNA in a buffer solution. Image courtesy of Keysight Technologies
MAC mode imaging of lambda phage DNA in a buffer solution. Image courtesy of Keysight Technologies

On the NANOSENSORS Special Developments List you will find all the cantilevers you need to continue working with MAC Mode.

Keysight TYPE II MAC Levers (PN: N9812x) – NANOSENSORS special development code: SD-MAC-Type2

Keysight TYPE VII MAC Levers (PN: N9866x) – NANOSENSORS special development code: SD-MAC-Type7

Keysight TYPE VIII MAC Levers (PN: N9867x) – NANOSENSORS special development code: SD-MAC-Type8

Keysight TYPE IX MAC Levers (PN: N9811x) – NANOSENSORS special development code: SD-MAC-Type9

MAC Mode Cantilevers for Keysight, Agilent and Molecular Imaging Atomic Force Microscopy
MAC Mode Cantilevers for Keysight, Agilent and Molecular Imaging Scanning Probe Microscopes