NT-MDT in the USA

Follow up on 2014 MRS Fall Meeting & Exhibition in Boston

Traditionally, the MRS Fall meeting is a large gathering of US and international scientists, and SPM-related symposiums always attract their attention. This year the attendees paid a special awareness to symposium PP: Advances in Scanning Probe Microscopy for Multimodal Imaging at the Nanoscale, co-sponsored by NT-MDT. The latest developments of techniques, which offer an optical resolution below the diffraction limit as well as chemical identification, were presented and discussed at this well attended meeting. We have also participated in this event by contributing two talks, and the same topic was a subject of our live demonstration of Tip Enhanced Raman Scattering on different samples, which was performed at one of our two booths. At another booth, NT-MDT has introduced a novel Thermal Cabinet for our SPM microscopes. The attractive cabinet provides not only microscope isolation fr om the acoustic noise and mechanical vibrations, but also ensures unique temperature stability with variations less than 0.01 degree. This instrument environment enables low thermal drift SPM measurement, which is important for many applications including but not lim ited to high-resolution imaging in different AFM modes (amplitude modulation, Hybrid and contact modes).

From the Social Networks

Several groups of the professional Internet network “LinkedIn” are involved in discussions about different aspects of scanning probe microscopy. One of the recent topics of “Scanning Probe Microscopy Society” is the novel approach in recording and analysis of force curves in Hybrid mode, which is the non-resonant oscillatory technique, introduced a couple of years ago by NT-MDT. The related document describing IsoDynamic Force Microscopy can be found at https://www.youtube.com/watch?v=_ftYMn-7te0. It contains a short movie presenting the visualization of elastic depression of poly (dimethyl siloxane) lamellar structures, which was recorded simultaneously with the force curves. Actually, the use of the force curves in AFM modes for the force control during imaging is also complemented by their on-line and off-line analysis as well as for the extraction of the local mechanical and electric properties simultaneously with the surface profiling. A new Application Note, in which these questions are considered in details, is in progress.

From the Laboratories

Thermoelectric measurements with AFM have been demonstrated by several research groups, and this method becomes a valuable addition to the family of AFM-based electric modes. The essence of this method is a precise detection of the voltage between the Pt-coated AFM probe and a sample and its changes at different temperatures. This phenomenon is broadly used in thermocouples and described by Seebeck coefficient which depends on the sample chemical nature. Our attention to the AFM thermoelectric measurements was inspired by the collaborative efforts with the group of Prof. Rachel Segalman (UCSB), whose earlier efforts has been documented in the paper: P. Reddy et al Science 315, 1568 (2007). The straight demonstration of this effect has been achieved in studies of an incomplete metal alloy of Bi and Sn. These metals are characterized by substantially different Seebeck coefficients: Bi – 72mV/˚C, Sn – 1.5mV/˚C. The image below shows the voltage map, which was recorded at elevated temperature of 55˚C. The distinctive contrast of different domains (practically not-noticeable at room temperature) allows their assignment to the individual constituents of this alloy. This is one of the possible ways of compositional mapping of the heterogeneous materials. Single-pass Kelvin Force Microscopy and quantitative nanomechanical measurements in the Hybrid mode were already described in NT-MDT applications related to the Bi/Sn alloy. It is worth noting that the AFM-based thermoelectric study helped to reveal the local defects in epitaxial graphene: S. Cho et al. Nature Materials 12, 913 (2013)

Forthcoming NT-MDT Events: 2015

January 14: Webinar “Characterization of Materials with a Combined AFM/Raman Microscope” based on the AFM/Raman data obtained in the combined Raman microscope DXR of Thermo Fisher Scientific and AFM unit NTEGRA Spectra from NT-MDT.
February: NT-MDT AFM/Raman Workshop at Carnegie Mellon University (Pittsburgh, PA), which includes technical presentations and demonstration sessions on several NT-MDT microscope.

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