Bio
Dr. Partha Pratim Das is an Application Scientist at NanoMEGAS SPRL, Belgium. He received his MS degree in Chemical Sciences from the Indian Institute of Science, Bangalore, India, and his Ph.D. degree in Material Science at UZH Zurich, Switzerland, in the year 2012 with a thesis on modeling diffuse scattering from single crystal X-ray diffraction data. Diffuse scattering is related to disorder present in the material. After his Ph.D., he joined NanoMEGAS SPRL as an Application Scientist in 2012 to support the company’s effort to establish Precession Electron Diffraction as a tool to solve complex nanomaterial structures. His current research interests focus on applying and developing transmission electron microscopy techniques for solving structures of beam-sensitive pharmaceutical materials and understanding disorders in amorphous/nanocrystalline material using pair distribution functions. He is the author/coauthor of more than 30 publications in international Journals and has organized/co-organized more than 15 international workshops, including a workshop in IUCR2017, Hyderabad, with more than 100 participants.

Talk
Abstract: In this presentation, Astar tool will be described. By taking control of the electron beam, an area of interest is scanned, and all diffraction patterns are recorded. Precession electron diffraction (PED) is used to increase phase and orientation signature. In the second step, PED patterns are compared to a database through template matching [1] procedure, results are then presented as phase and orientation maps, using different reliability criteria. The recognition software is developed at SIMAP laboratory, whereas the hardware’s are produced by Nanomegas company [2,3]. Astar tool is now well established as a powerful characterization tool at the nano and mesoscale to assess phase occurrence or to measure grains at the nanometer scale. Main publications come from metallurgy, semiconductor and minerals communities. In this talk recent examples of Astar investigation will be presented such as the use of direct detection camera to increase speed of acquisition on sensitive samples [4]. [1] E. F. Rauch et al., Arch. Metall. Mater. 50, 87–99, 2005 [2] E. F. Rauch et al., Solid State Phenomena. 186, 13-15, 2012 [3] E. F. Rauch et al., Materials Characterization, 98, 1-9, 2014 [4] J. H. Lim et al., The Journal of Physical Chemistry Letters, 14(16), 3961-3969, 2023

Bio
Dr. Muriel Veron received her Engineering degree and her Ph.D. in Material Science and Engineering from Grenoble-INP, France. After completing her PhD in 1995, she joined McMaster University, Canada's Materials Science and Engineering Department as a Postdoctoral Research Associate. In 1996, she returned to France to take an Assistant Professor position at Grenoble-INP and SIMaP Laboratory (Material Science and Process Laboratory). She was made a professor in 2008. Since 2009, she has held the post of Deputy Director of the engineering school Phelma, with 1200 students and important international collaborations. In July 2011, she was awarded the APERAM Rene Castro Prize for her contributions to steel phase transformations and alloy design. In the Metal Physics department at SIMaP, her research focuses on the coupling between microstructure and mechanical properties. She works closely with industrial collaborators on fundamental and applied topics. Muriel Veron has contributed significantly to the development of TEM automated orientation mapping in association with the pioneering work of Dr. Edgar Rauch (CNRS); this has resulted in orientation and phase maps at the nanometer scale and provided the scientific and industrial communities with a new and powerful tool to investigate materials. she published more than 120 articles including conference proceedings, organized more than 25 workshops dedicated to crystallography and phase/orientation mapping tool (ASTAR), and supervised 20 PhD students.

Talk
Tile of the Presentation: Strength and weakness of COM/Template Matching and related 4D-STEM analysis for Electric Field measurements. Abstract: In the last 10 years, there have been many publications analyzing the accuracy of either Center Of Mass (COM) analysis of 4D-STEM data sets, what we called COM_4D-STEM (for instance, [1]) that is partly related to the analysis of Differential Phase Contrast (DPC) experiments [2]. In this talk, a synthesis of these works will be presented, as well as some recent publications performed on this subject. In particular, the interest in using precession [3], what we call now 4D-SPED (4D scanning Precession Electron Diffraction), or working by references using in situ biasing [4] will be evocated. [1] K. Müller et al., Nat Commun, 5, 5653, 2014 [2] H. G. Brown et al., Ultramicroscopy, 182, 169 178, 2017 [3] L. Bruas et al., Journal of Applied Physics, 127 (20), 205703, 2020 [4] B. C. da Silva et al., Applied Physics Letters, 121 (12),123503, 2022

Bio
Jean-Luc ROUVIERE is a senior scientist at the French Alternative Energy and Atomic Energy Commission (CEA), where he uses and develops Transmission Electron Microscopy (TEM). After graduating from the Ecole Polytechnique in Paris in 1985, he joined CEA in Grenoble to complete his Ph.D. on determining the atomic structure of Si grain boundaries using High-Resolution TEM (HR-TEM). His PhD work earned him the Pierre Favard Prize. In 1990-1991, he was a visiting scientist at AT&T Bell Labs in Holmdell, US, where he applied QuantiTEM to diffusion studies. In 2005, he and the research laboratory he belongs to joined the Minatec characterization platform, which combines various advanced characterization tools, such as FIB, TEM, SIMS, and Atom Probe. His main research achievements include (i) interface and (ii) strain map studies in semiconductors using various TEM techniques based on high-resolution images (TEM and STEM) or Electron Diffraction Maps (eDM), also known as 4D-STEM. He also promotes the use of Scanning Precession Electron Diffraction (4D-SPED). Currently, he is focusing on using eDM to obtain information about the electric, magnetic, and atomic structure of nano-objects or devices.

Talk
Tile of the Presentation: Beam-sensitive nano-crystals: a double challenge for crystallographic structure solution Abstract: The double challenge can be tackled by electron crystallography, where single crystal diffraction data can be obtained from nano-metric crystals [1]. In addition, electron diffraction is very efficient for obtaining structural information at low amounts of beam damage [2]. For beam-sensitive materials, the success of structure solution and refinement depends on the ability to obtain high-quality diffraction data using a dose low enough so that it does not alter the structure of the crystal. In this contribution, we present examples of structures where a total dose of only a few e-/Ų already destroys important features of the crystalline structure. The recently introduced Low-Dose Electron Tomography (LD-EDT) [3] allowed us to record full single crystal diffraction sets from sub-micron crystals with total doses of less than 0.15 e-/Ų [4]. These datasets were of high quality, and the structures could be solved ab initio and subsequently refined, considering the dynamical diffraction effects of electrons. [1] M. Gemmi et al., ACS Cent. Sci., 5, 8, 1315–1329, 2019 [2] R. Henderson, Quarterly Reviews of Biophysics, 28 (2), 171-193, 1995 [3] S. Kodjikian et al., Ultramicroscopy, 200, 12-19, 2019 [4] H. Klein et al., Symmetry, 14 (2), 245, 2022

Bio
Holger Klein is an Associate Professor at the Université Grenoble Alpes working at the Néel Institute, Grenoble, France. He has been involved in electron crystallography by precession electron diffraction since 2006. He is a former Chair (2011 – 2015) and Co-chair (2015 – 2018) of the Special Interest Group on electron crystallography of the European Crystallographic Association and has participated as a lecturer in several schools on electron crystallography. He worked mainly on oxide structures before his interest shifted towards beam-sensitive materials like natural minerals and metal-organic-frameworks in recent years.