Du fait de leur propriétés de luminescence uniques et de leur grande photostabilité, les oxydes à base d’ions terres rares ont connu un développement rapide avec des applications allant de l’éclairage, l’affichage ou l’amplification optique à des domaines émergents tels que les technologies quantiques, la biodétection ou la nanomédecine. Dans le contexte de la transition énergétique, une question-clé concerne le coût et la disponibilité des terres rares dans les années à venir, qu’ils soient utilisés comme ions dopants luminescents (Yb³⁺, Ce³⁺, Nd³⁺) ou comme formateurs de cristaux hôtes pour ces dopants. Nos travaux visent à explorer de nouvelles compositions de cristaux hôtes pour réduire la pression sur les chaînes d’approvisionnement en utilisant des terres rares de plus faible pureté issues de l’économie circulaire ou en cherchant à les substituer par des éléments non critiques.

Magnetic materials are of outmost importance in modern life, they are at the heart of motors, generators, actuators and detectors. The research for improved performance is driven by the need to reduce energy consumption and provide optimise material for each applications. The best materials to date for electric vehicles, windmill or greenhouse magnetic refrigerant are all containing rare-earth elements (R) which have been considered as critical material by the European community as well as the USA. The need for such elements reflects their importance for new technologies as well as the risk of using such elements mostly supplied by China. The R-M phases based on rare-earth (R) and transition metals (M) are fascinating materials from both applied and fundamental viewpoints. The R-M compounds are however complex materials and need fundamental studies to master their magnetic properties and optimize their performances.

Elaboration et caractérisation d’intermetalliques obtenus par solidification rapide

La transition énergétique vers des sources d’énergie plus durables et respectueuses de l’environnement est devenu un enjeu majeur. Dans ce contexte, l’hydrogène apparaît comme une des solutions prometteuses : il est largement répandu sur Terre et a peu d’impact sur l’empreinte carbone. Toutefois l’utilisation de l’hydrogène à grande échelle nécessite de pouvoir le stocker de manière compacte, ce qui reste un des plus grands défis de la recherche actuelle. Le/la stagiaire utilisera le microscope électronique en transmission de dernière génération de l’Institut Néel pour caractériser la structure de matériaux particulièrement pertinents pour le stockage d’hydrogène.

The combination of superconducting and semiconducting materials at nm length scales is an intensely studied topic as new device functionalities can be realized by combining these material combinations at such small length scales. In particular, these structures are regarded as promising building blocks for quantum computing. More specifically, the Al-Ge and Al-Si material combination has been studied in depth in our groups during the last 10 years, both for its structural aspect by using transmission electron microscopy (TEM) as well as by low temperature transport, in collaboration with researchers at the Technical University of Vienna, Austria.

Long range electric and magnetic fields are present all around us in devices, where electric fields on atomic length scales are present in all matter. However, it remains challenging to measure the strength of these fields accurately and with high spatial resolution. Several Transmission Electron Microscopy (TEM) based techniques exist, sensitive to internal fields. TEM is of particular interest in this respect, since (i) the electron traverses the sample, and can therefore probe all fields it traverses, and (ii) due to the very high spatial resolution that can be obtained in TEM.

In this internship we will study layered Ln_n+1Ni_nO_3n+1 nickelates which become high T_c superconductors under high pressure, after a structural transition occured. The aim is to understand the close relationship between superconductivity and this crystallographic transition, then the related superconductivity mechanism. Another goal will be to stabilize this superconducting state at ambient pressure in such nickelates family.

Are you interested in working in a large collaborative team to advance the design of next-generation energy storage materials? You will be based at the Institut Néel and the SyMMES laboratory (CEA) within the GIANT campus of Grenoble. Your role will involve characterizing and performing electrochemical measurements on new cathode materials prepared using the niche technique of Cold Sinter Processing (CSP), a technology poised to revolutionize the autonomy and safety of electric vehicles by enabling the production of new materials and devices at low energy costs.

Are you interested in working in a large collaborative team to advance the design of next-generation energy storage materials? You will be based at the Institut Néel and the LEPMI laboratory within the GIANT campus of Grenoble. Your role will involve characterizing and performing electrochemical measurements on new electrolytes prepared using the niche technique of Cold Sinter Processing (CSP), a technology poised to revolutionize the autonomy and safety of electric vehicles by enabling the production of new materials and devices at low energy costs.

A fully funded PhD project at Institut Néel / Université Grenoble Alpes in France. The start date must be between October and December 2024.

The project focuses on:

1. The growth of single crystals of new magnetoelectric oxide materials.
2. Their characterisation using in-house instruments (single-crystal XRD, magnetic and transport properties) and large-scale central facilities (neutrons, synchrotron XRD).
3. Modification of their properties through electrochemical cation (de)intercalation.

The aim of this thesis project is to solve the structures of coordination polymers using electron crystallography, and thus make a significant contribution to the search for new materials in this field. In this thesis project, we will use electron diffraction, since for this technique nanometric crystals are sufficient for solving the structures. A combination of methods and strategies from structural biology and materials science will enable us to optimize data acquisition and processing.

The thesis will comprise several stages:

• Performing electron diffraction experiments in a transmission electron microscope under low-dose conditions on coordination polymers.
• Optimization of experimental conditions to obtain diffracted intensity sets of the highest quality.
• Combining data processing methods from structural biology and materials science.
• Structural resolution of coordination polymers from 3D ED data.
• Structure refinement from 3D ED and/or X-ray powder diffraction data.