Functional properties optimization of Composite nanomaterials : towards a smart control of the functionalities

• Auteur / Autrice : Lino Martinez
• Direction : Silvana Mercone, Frédéric Schoenstein
• Type : Projet de thèse
• Discipline(s) : Doc sciences des materiaux
• Date : Inscription en doctorat le 12/10/2019
• Etablissement(s) : Paris 13
• Ecole(s) doctorale(s) : École doctorale Galilée (Villetaneuse, Seine-Saint-Denis)

Résumé

The main objectives of this project will be to elaborate and characterize new original architectures based on bi-dimensional hetero-nanostructures: size and shape controlled magnetostrictive and/or coercive Co and Fe based nano-magnets that will be intimately mixed to a ferroelectric matrix (organic polymeric one or inorganic one). In order to overcome the fluctuation phenomena destabilizing the magnetic properties of the nano-objects, we are willing to work mainly on anisotropic ferromagnetic nanoparticles. Two main chemical methods have been developed to synthesize them. The first method consists of conducting chemical or electrochemical reduction in the pores of inorganic or organic templates such as alumina, polycarbonate membranes. The second method consists of reduction in solution without the presence of a template agent. We have recently reported on an alternative and friendly environmental approach for the fabrication of Ni nanofibers and nanowires in the absence of any template, substrate, surfactant, or strong reducing agent such as hydrazine. It consists on conducting reducing chemical reaction in a polyol medium under applied external field. It takes benefit from the properties of polyol which act as solvent, complexing and reducing agents to produce a great variety of inorganic materials (oxides, metals, layered hydroxyl salts). The external applied field likely controls the nucleation and growth processes. In this context we hopefully will be able to stabilize well-organized very fine iron oxide nanoparticles with very high coercivity. This will open a powerfull perspective in permanent magnet applications, as it will allow a strong replacement of rare earth systems by iron-based nanomaterials.