More than two decades ago has emerged a new technology exploiting electron spins to convey information within an electric circuitry. This technology, known as spintronics, translates in advantages such as nonvolatile storage technology, fast-data processing speed and low-power consumption. The working principle of a spintronic device is to generate a non-equilibrium spin population and to detect it. However, creation and detection occurs in different regions of the device. During the transfer process from one region to the other, the spin population tends to relax towards its non spin-polarized equilibrium state weakening then the efficiency of the device. One of the central research areas in spintronics therefore aims at perfecting this transfer process. Present efforts involve improving existing technology or finding novel radical ways of manipulating spin-polarized electrons. The SPINCOMM project is in line with this second approach and falls in the context of molecular spintronics. The purpose of project SPINCOMM is to carry out the first fundamental investigation of spin transport across a single organometallic wire. To achieve this ambitious goal, a pioneering bottom-up approach will be implemented through four innovating strategies: 1) SIMPLIFICATION: The wires will have a multi-decker architecture where single transition-metal atoms alternate with cyclopentadienyl rings (C5H5). Strikingly, these wires have been predicted to display a 100% spin-filtering efficiency over a wide bias range. 2) CONTROL: Transport measurements will be carried out with a low-temperature scanning tunneling microscope (STM) operated in ultrahigh vacuum. The molecules will be deposited onto a well-calibrated surface and then contacted by the STM tip. Junction formation with a single multi-decker molecule will be greatly facilitated by the upstanding adsorption geometry onto the surface. Precise information about the binding properties of the multi-decker molecule to the electrodes will be available. XMCD measurements will be carried out independently to carefully characterize the magnetic status of the molecules. 3) CUSTOMIZATION: The chemical composition of the molecule and its length will be modified directly in the STM junction to optimize spin transport. Moreover, the material of tip and surface will be changed in order to tackle different aspects of spin transport. These essentially consist in the Kondo effect (non-magnetic tip and surface) and its interplay with spin-polarized electrons (ferromagnetic tip and a non-magnetic surface), as well as a transport across a single-molecule spin-valve (ferromagnetic tip and surface). 4) SIMULATION: Given the unprecedented microscopic control exerted over the junction and the simplified molecular architecture employed, the experimental data will be highly amenable to first-principle calculations. State-of-the-art density functional theory and transport calculations will be used to unravel the key mechanisms governing spin transport, along with non-equilibrium and correlated calculations to treat the Kondo problem. With the know-how acquired, the mono-decker architecture of the molecule will be exploited for developing a new spin-sensitive microscopy. A molecular tip comprising a mono-decker molecule will be used to record “contact images” of the surface. Surfaces with opposite magnetizations are expected to produce a higher contrast than the one accessible to SP-STM due to the nearly ideal spin-filtering effect of the mono-decker molecule. With spin-polarized contact microscopy it will be possible to map the spin-polarized properties of surfaces and nanostructures with atomic-scale spatial resolution and to assess the impact of defects, surface impurities, and electronic inhomogeneities on spin transport. We expect this technique to develop quickly and to have a success similar to one of SP-STM in these last ten years.

This project focuses on three iron-base alloys that have growing potential for high-temperature, high-strength and strong- magnet applications: Fe-Cr, Fe-Mn and Fe-Co. Because of the key role of magnetism, an innovative materials design based on advanced modeling approaches is necessary to control key properties of these materials. Such a design strategy requires the combination of (i) highly accurate methods to determine atomic features with (ii) efficient coarse-graining techniques to access target physical properties and to perform the screening of materials compositions. For the former, density functional theory (DFT) has for many materials classes already proven to be a highly successful tool. For Fe-based alloys, however, a critical bottleneck is the role that magnetic ordering, excitations and transitions have on thermodynamic, defect and kinetic properties. Therefore, a complete and accurate modeling of magnetism is urgently needed to address the materials-design challenges: the resistance to radiation damage related to the chemical decomposition in Fe-Cr, the grain-boundary embrittlement in ferritic Fe-Mn and the high-strength of austenitic Fe-Mn, and the phase ordering and the relative stability of a and ? phases in Fe-Co cannot be fully understood without properly accounting for the magnetic effects. The novelty of the current approach is twofold: First, on the DFT-side, we will make use of the recent important progress in treating magnetism in pure idealized Fe lattices, in order to go towards an accurate modeling of magnetic multi-component systems with point/extended defects, and beyond the standard collinear approximation. Second, we will develop new methods that allow us to bridge the gap between (i) highly accurate electronic calculations and (ii) large-scale atomistic thermodynamic and kinetic simulations for iron based alloys by – and this is decisive – fully taking into account the impact of magnetism on defect properties, diffusion and microstructural evolution. For the latter, lattice-based effective interaction models (EIMs) and tight-binding (TB) models will be developed based on data from DFT, including magnetic configurations, excitations and transitions. This will allow us to provide a coherent description of the role of magnetism on various properties of Fe-based alloys at different length scales and at finite temperature. It will further give us the ability to perform the optimization of key parameters controlling the relevant properties like phase decomposition in Fe-Cr, phase ordering in Fe-Co or decohesion of grain boundaries in Fe-Mn. Dedicated experiments in bulk alloys and along intergranular / interphase boundaries grown on demand will be performed in the project, which are essential for verifying the robustness of the theoretical predictions. The three chosen alloys exhibit a large variety of magnetic behavior. The methods developed and applied in this proposal are therefore expected to be transferrable to the modeling of other magnetic materials. The results of our simulations will lead to the improvement of thermo¬dynamic and diffusion databases and tools (such as DICTRA) that are nowadays routinely used in industrial R&D but that at present have difficulties in accounting for magnetism. In this way a better and more systematic understanding of the role of magnetism in Fe-based alloys will help to improve significantly the predictive power of the simulations and thus contribute to a more efficient and accurate development of new steel grades. Once fully implemented, the availability of such computational tools is expected to boost the efficiency, change the strategy in designing new steel grades and to form an important contribution for the future competitiveness of steelmakers.

Many imaging techniques, particularly in environmental transmission electron microscopy (ETEM), generate images with degraded signal-to-noise ratio, contrast and spatio-temporal resolution, which hamper quantification and reliable interpretation of data. Moreover, the extraction of structural information from these images relies on manual acquisition and local structural identification which does not allow statistical analysis of the data and necessarily introduces a human bias carried out at the post-processing stage. The general aim of the ARTEMIA project is to develop a ground-breaking deep learning-based framework for in situ microscopy in liquid and gaseous media allowing the automated, high throughput, real-time acquisition and analysis of ETEM image sequences.Our framework will integrate aberration-corrected in situ ETEM imaging using windowed liquid/gas nanoreactors with denoising and resolution enhancement scheme set up using convolutional neural network (CNN). For model training, datasets consisting of simulated liquid- and gas-phase TEM images will be generated by by atomistic simulations including instrumental noise and imperfections of the microscope optics. In the ARTEMIA project, the CNN models will be applied to the study of two crystalline samples with complementary structural characteristics and electron beam sensitivity, model gold nanoparticles (Au NPs) and microporous zeolite, in reactive gas and/or liquid environments. Our scientific aim will be to gain further mechanistic understanding ofthe growth of model Au NPs in liquid phase and their reactivity in oxidizing and reducing gas environments on one hand and the steaming process of beam-sensitive zeolite on the other hand. The consortium comprises three academic partners (MPQ, LEM, IPCMS) and an EPIC partner (IFPEN) with complementary expertise in liquid and gas ETEM, data science and image processing with special focus on deep learning approaches, atomic modelling and TEM image simulation.

Project Summary The ASTRID MATURATIION CARPE DIEM MAGIS project aims at developing new materials of millimeter thickness on a semi-industrial scale to absorb electromagnetic waves in the widest range within the spectral window 1-6 GHz. This project follows the ANR ASTRID CARPE DIEM project in which these materials were studied, and then developed and characterized on the laboratory scale. Applications concern the electromagnetic shielding of electronic components in the civil sphere and the stealth technology in the military field. The proposed work of maturation will first focus on manufacturing of ferromagnetic flakes of various chemical compositions in semi-industrial quantity while respecting the optimal geometric characteristics of these flakes, deduced from the CARPE DIEM project. The next stage is to disperse these flakes in an elastomer matrix using a consistent process of industrialization. The latter must allow to achieve an homogeneous flakes dispersion and maintain, within the matrix, the high degree of flakes orientation obtained on the laboratory scale. Composite plates with decimeter lateral sizes will be then fabricated. Their microwave absorption performance will be determined using free space measurements. In parallel, research activities will be conducted on micrometer-sized flakes on the laboratory scale. Lateral size reduction of flakes results in a decrease of the real effective permittivity of the composite and a change in the permeability spectrum. Interest of these micrometer-sized flakes will be evaluated in terms of microwave absorbing materials. This project is mainly an experimental work including the synthesis of composite materials and their microwave characterizations, consolidated by a modeling activity. For this work, the CARPE DIEM MAGIS project gathers 4 partners : DASSAULT AVIATION, MARION TECHNOLOGIES, PAULSTRA snc and l’Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS) with complementary skills.

The project deals with the design of new Ti/polymer(P)/Ti and P/Ti/P sheets for biomedical applications, controlling their interface and adjusting their mechanical properties and shaping behaviour. Elaboration, process development, analysis of the properties, and their forming limits will be performed in synergy between three partners with the goals: 1. Developing strategies to design P/Ti interfaces in sandwich sheets (SMs) to employ surface-confined, resin free compatible polymer layers as adhesives for a strong bond between P and Ti for final shaping without delamination. “Grafting from” and “Grafting to” methods will be used, allowing a larger choice of monomers. “Grafting from” to produce Ti/P/Ti SMs with modulated properties in polymer by designing the glass transition temperature of the selected polymer. A polymerization initiator will be grafted at NaOH modified-Ti surface via a phosphonate anchor. Linear polymer chains of various molar masses, as homopolymers or copolymers types will be grown from the initiator using a controlled radical polymerization process. The monomers used will be as methyl methacrylate (MMA), n-butyl methacrylate (nBMA) and methyl acrylate (MA). A mixture of monomers will be used for the synthesis of random copolymers.. Grafting to” for bioactive thick polymer layers on Ti of homo and copolymers of sodium 4-styrenesulfonate (NaSS) and MA. A readily accessible anchor incorporating both an anchoring group (catechol), capable of forming a robust, stable monolayer, and a clickable function allowing the modular and efficient post-functionalization of the Ti surface will be used. In parallel, polymers or copolymers bearing thiol end groups will be attached using thiolene click reaction onto the monolayer. Linear polymer chains of various molar masses, as homo-polymers or co-polymers types will be synthetized by a controlled radical polymerization to give thiol-ends. In order to obtain thiol end polymers or copolymers, addition-fragmentation transfer polymerization will be chosen. The monomers used will be NaSS and/or MMA and a mixture of monomers to synthetize statistical copolymers. 2. Fabricating Ti/P/Ti or P/Ti/P SMs, SMs will be processed at IMET by bonding modified Ti sheets to commercially or in laboratory made polymer foils of defined thicknesses (e.g. PMMA or PMMA-co-PBMA foils or PMMA-co-PNaSS foil). The feasibility of the “Grafting from” method was stated in DFG project PA 837/44-1 3. Tailoring the mechanical properties close to the bones’ ones. Mechanical and shaping properties will be studied and controlled by modulating the molecular and structural parameters of the polymers or the ratio of the layer thicknesses. 4. Stability and cytocompatibility of the SMs will be conducted. The advantages of these systems usable for cranioplasty and mandible surgery will be lightweight SMs with mechanical properties designable in the range of bones’ ones and improved thermal and acoustic properties compared to Ti.