X-ray diffraction recently celebrated its centenary ; in the space of a century, it has revealed the arrangement of atoms in crystallized matter. While single-crystal diffraction is unrivalled for resolving structures, powder diffraction, via Rietveld refinements, provides precise quantitative information on atomic positions, interatomic distances and the microstructure (size, microdeformation) of samples.
Neutron diffraction, more confidential due to the difficulty of producing neutrons in quantity, overcomes some of the limitations encountered with X-rays; light atoms (H, Li.) can be precisely localized, and atoms close to each other in the Mendeleiev table (Mn, Fe, Co, Ni.) diffract with high contrast; in fact, neutrons interact with the nucleus of atoms and not with the electron cloud (as is the case with X-rays).
On the other hand, neutron diffraction is the method of choice for obtaining magnetic structures, the knowledge of which provides a better understanding of compounds with remarkable electronic properties (multiferroics, superconductors...). The seminar, illustrated by examples from battery materials research, concludes with a presentation on current and future cutting-edge techniques. In particular, we look at how to study lamellar bonded compounds, as well as the possibilities offered by free-electron lasers.
