Materials science research involves the investigation of the relationship between the structure of the materials and their properties. The structure-property relationship is the basis for the rational design of new materials with specific properties. Materials research is thus the underlying motivation for a large fraction of research at the ESRF. This section presents some examples that cannot easily be fitted into specific chapters.

The clear tendency in materials research is the utilisation of the unique properties of the X-ray source i.e. the high brilliance, the high energy, the microfocussing capability and its coherence. Many of the experiments thus deal with time-resolved studies, non-ambient conditions such as high pressure or temperature, and mapping of stresses and strains.

The first two studies deal with liquids or liquid alloys. An EXAFS study of the Hg-Rb liquid alloy has been performed in order to understand the difference in conductivity of mercury if non-alkali or alkali metals are added. The study suggests that the alkali metals are involved in a solvation process with the mercury reducing the conductivity of the alloy. The second example deals with the nucleation process in under-cooled liquid metals. This study presents a novel general method for determining the nucleation rates. In this case palladium droplets dispersed in Al2O3 powders are studied. The method is based on a non-destructive use of the phase-sensitivity of X-ray absorption above the core-electron absorption edges.

Microstructure and grain structure are important factors determining the properties of materials. The new "3D-microscope" at ID11 has been used to develop an in situ method for determining the tensile deformation on many individual grains, of sizes down to a micrometre. The study indicates that present models are not sufficient for predictions of the effect of deformations. Magnetic elements exhibit interesting nanostructural properties. In an EXAFS experiments on Co atoms implanted in an Ag matrix, the effect of heat treatment of the samples showed that Co dimers or larger clusters are formed as a function of temperature.

Three examples illustrate the widespread use of high pressures to study materials. The first example deals with the novel superconductor MgB2. Here the structural properties have been studied by angle-resolved X-ray diffraction up to pressures of 40 GPa. X-ray diffraction shows no structural instability.

The observation of colossal magnetoresistance in perovskite manganites has prompted a high-pressure study of LaMnO3 up to pressures of 40 GPa. In the high-pressure study it was observed that between 18 and 32 GPa an intermediate insulating structure with suppressed Jahn Teller distortion is found showing that the insulating phase is not caused by the JT effect. The final high-pressure example deals with covalent semiconductors. The III-IV zincblende structures are expected to transform from a NaCl structure to a CsCl structure under pressure. Here it is shown that InAs does not convert to a CsCl structure at high pressures but rather to a site-disordered orthorhombic Pnma structure.

The high X-ray intensities available make it possible to perform fast in situ studies. In a first example the oxidation of SrFe0.97Cr0.3O2.8 occurring at high temperatures when a N2 atmosphere is replaced by O2 has been studied showing a two-step oxidation process. In the final example, an in situ study of a working Li-ion battery is presented. Very high X-ray energies (87.5 keV) were used to penetrate the lithium battery and record powder diffraction patterns as a function of the charging cycle.