Referent: Yannick Mugnier
This theme focuses on the preparation and structural, thermodynamic and multifunctional characterization of (nano)-materials with high added value.
It aims at establishing or revisiting, in particular for massive materials of the alloys and metallic oxides type, the equilibrium diagrams between phases of binary and higher order systems, and to feed the diagrammatic (liquidus temperature, invariant equilibria, structural transformations, ...) and integral (heat capacity, enthalpy of academics, ...) databases for the thermodynamic modelling of systems. The objective is to use this knowledge to develop innovative materials and to contribute to the control and optimization of industrial processes, for example, in the fields of nuclear safety (Zr-based alloys) and electroerosion (control of surface deposited phases).
(a) ISEM image of an In-Zr alloy of composition 66.7 at%Zr alloy produced by powder metallurgy andannealed at 1000°C. (b) Evidence of eutectoid decomposition in a(b) Evidence of a eutectoid decomposition in an InZr alloy of composition 81.5 at%Zr. (c) Example of quantitative refinement of type Rietveld type of a multiphase compound.
At the nanoscale, research is focused on establishing the reaction and crystallization mechanisms of materials with non-centrosymmetric crystal structure (LiNbO3, BiFeO3, LiTaO3 and Sillenite-like phases) in order to control their final morphology. These harmonic nanoparticles have extremely rich non-linear optical properties (in terms of photostability, wavelength flexibility, imaging depth and response time) which are quantified and used in the biomedical field. This concerns early diagnosis after functionalization of their surface for specific marking of cancer cells or targeted release of anti-cancer molecules on demand.
(a) Image multiphoton of lung cancer cells specifically labeled with LiNbO3 nanocrystals, whose second harmonic signal appears in blue and (b) corresponding TEM imaging of the nanocrystals. (c) Dispositive of spectroscopy ofs signals non-linear optical signals illustrating here a second harmonic scattering from aa colloidal suspension colloidal suspension of nanocrystals for an excitation in the infrared.