Aile 1, Niveau 6
The Magnetism team is devoted to the study of exotic magnetic properties in condensed matter. For more than 20 years, we are specialized in electron spin resonance (ESR) in paramagnetic, ferromagnetic and antiferromagnetic materials.
We study materials for purely fundamental science like low-dimensional strongly correlated magnets (like spin chains, frustration, spin liquids) as well as material for potential applications in spintronics (ferromagnetic, multiferroic) or in quantum information processing (quantum coherence in diluted paramagnets).
The main line of research is concerned with intrinsic properties of ferromagnetic materials, such as spontaneous magnetisation, Curie temperature and magnetic anisotropy. In particular, I derived a formula faithfully describing the shape of the thermal dependence of spontaneous magnetization. A further area of activity is investigation of magnetocaloric effect in strong magnetic fields, in collaboration with colleagues at the High-Field Laboratory in Dresden-Rossendorf. The record value of the effect, observed by us in a single crystal of terbium under an applied magnetic field of 67 T, is ∆T = 73 K. I am also involved in a search of new intermetallic compounds for permanent-magnet applications (with the Darmstadt group). A promising technique in this direction is synthesis under very high pressure (~ 1010 Pa).
The team focus on the generation and manipulation of optically-excited magnetic quantum states in semiconducting nanostructures. In particular, non-magnetic nanoparticles of ZnO have been recently proved by us to transit toward a localized quasi-stable magnetic excited state, when illuminated by a minimal wavelength of about 405 nm. After illumination removal, these surface magnetic states are non-radiatively relaxed by phonon scattering above 80 K and are permanent under this about 50 K. Pulse EPR has been successfully applied to this system, thus opening the way to the manipulation and monitoring of magnetic quantum states in stable and robust inorganic nanoparticles.
|Spectromètre RPE, Bruker EMX
Magnétomètre à SQUID,
Système de mesures de susceptibilité AC et DC MAGLAB 2000