Description du sujet de thèse

In magnetic materials, spin excitations can propagate in the form of collective phenomena known as magnons. This propagation, which can be likened to a spin current, is characterized by the absence of electric charge transport in the medium, thus eliminating the energy losses usually associated with it. As a result, magnons offer a promising solution for transmitting information, opening up innovative technological horizons for the future. The aim of this project is to explore the ultrafast behaviour of magnons in antiferromagnetically coupled perovskite materials. It aims to identify and analyse in detail the factors that influence their propagation, from the chemical environment, notably the ligand field, to the angular momentum transfer between the spin and the crystal lattice supporting the excitation. We will use state-of-the-art experimental techniques, optimized for femtosecond time resolution, combined with rigorous theoretical models. Our approach will take advantage of the chemical selectivity of X-ray spectroscopic methods, notably resonant inelastic X-ray scattering. The data obtained will form the basis for research into the effects of this method applied to the most suitable candidate materials for information transmission. The PhD position is funded for three years through the CNRS program 80|PRIME – 2025.

Contexte de travail

Located in the heart of Paris, on the prestigious Pierre et Marie Curie campus, the PhD student will benefit from a first-rate academic and research infrastructure, while evolving in a rich and scientifically stimulating environment. Sorbonne Université is one of France's leading universities, dedicated to the humanities, health, science and engineering.

We are looking for a candidate with a Master's degree in physical chemistry, physics or related disciplines. Practical experience on experimental devices, as well as an interest in data analysis and programming, would be highly appreciated. The ideal candidate will be collaborative and willing to work as part of a team in the context of national and international partnerships.

Contraintes et risques

Experimental work will include measurement campaigns, typically lasting a week (beamtimes), carried out on research infrastructures (synchrotron light sources and free-electron X-ray lasers) located in France and abroad.