Currently the best performing magnets are Nd-Fe-B and Sm-Co magnets. Their magnetic properties are due to the presence of rare earths, making them sensitive to oxidation. The most commonly used magnets are Sr-Fe-O hexaferrite magnets. They do not contain rare earth and have lower magnetic properties than magnets with rare earth, but they have the advantage of being resistant to oxidation and, above all, very inexpensive. Current research is aimed at developing new materials with properties comparable to, or even superior to, those of magnets with rare earth. Recent studies have been conducted on Al-Mn-C or Hf-Co alloys, but have not been successful. Another strategy is to increase the magnetic properties of existing magnets (Nd¬Fe-B or hexaferrites) by nanostructuring. Despite extensive work, no nanostructured material with superior properties than conventional Nd-Fe-B magnets has been developed. However, recent work on the nanostructure of hexaferrite magnets has shown that it must be possible to synthesise materials with superior properties than conventional hexaferrite magnets. Efforts should therefore focus on the development of innovative processes for obtaining a magnetic nanomaterial. From this point of view, solvothermal synthesis is a process that is particularly well suited for the synthesis of nanometric hexaferrites.The work carried out at the GPM in this field is currently being oriented in two ways. On the one hand, it involves synthesising and improving the magnetic properties of hexaferrite magnets by nanostructuring in the presence of pure iron. The presence of pure iron should increase the magnetisation of the material. Nanostructuring must maintain its resistance to demagnation. On the other hand, new methods of recycling used Nd-Fe-B magnets are being developed. The target materials will then be renewable and have a low energy footprint. In order to achieve this, a supercritical synthesis enclosure for the production of nanostructured magnetic powders according to the two channels described above is necessary. This is the subject of one of the acquisitions of this project, as well as a request for a doctoral allowance (allocation n°1).In the field of spintronics, the materials used consist either of nanoparticles dispersed in a non-magnetic matrix (the case of magnetic semiconductors) or of multilayer nanometrics (the case of materials for magnetic recording media). In heaven, the role of nanostructure, interfaces (between magnetic phase and non-magnetic phase, or between two magnetic phases), short or medium-range magnetic interactions and temperature are crucial.For the development of a diluted magnetic semiconductor (DMS) at room temperature, it is necessary to provide a systematic assessment of the implantation of transition metals in the semiconductor. Indeed, despite the many scattered experimental results and approximate theoretical simulations, no decisive conclusions can be drawn today on this potentially powerful system in the field of spintronics. In particular, SiC silicon carbide offers great potential as a device that can operate at high temperature and high frequency, and is already mature in the microelectronics industry. The first experiments with polytype 611-SiC implanted in iron (thesis by Cyril Dupeyrat-2009-Poitiers) were particularly concerned with the microstructural study of this system. This work was extended by Lamine Diallo’s thesis at the GPM-Rouen (planned 2016 support) which allowed us to understand the origin of magnetism