FE-BASED NANORODS FOR THE FABRICATION OF « GREEN » MAGNETS

Work package:
Magnetic materials play a major role in the current energy and societal transitions. However, the development of sustainable yet performant materials, without critical elements such as rare-earths (RE), remains a challenge [1,2]. This 6-month internship, which will be followed by a thesis, is part of a large- scale project involving 5 laboratories with complementary expertise in chemistry, physics, chemical engineering, artificial intelligence and data science, to develop iron-based nanorods (NRs) with optimized magnetic properties. The real scientific challenge consists in breaking the symmetry of the Fe crystalline structure while keeping an optimized aspect ratio, the growth of anisotropic particles requires the symmetry breaking of iron's crystalline structure. Such control will allow achieving magnet-like properties in assemblies. The LPCNO has been working for almost 10 years on the development of rare-earth-free magnets using a directed assembly approach of elementary building blocks (Fig 1a). To date, this work has been carried out on Co nanorods (NRs), synthesized by seeded growth (Fig 1b), and has led to high-performance integrated magnets [3,4]. The aim of this internship will be to transpose the seeded growth method on Fe NRs, the challenge relying on the need of breaking the symetry the crystal structure of Fe exhibit. An exploration of the range of parameters (nature of seeds, growth conditions, ligand concentration) will be undertaken during this internship. The particles obtained will be characterized by electron microscopy (TEM and SEM), diffraction (XRD) and X-ray scattering (SAXS, WAXS) and magnetometry (VSM), in close partnership with the other laboratories in the consortium.