Neutron diffraction in solid state sciences: instruments, data analysis and new materials.

Juan Rodríguez-Carvajal

Institute Laue-Langevin, BP 156, F-38042 Grenoble Cedex 9 (France)

jrc@ill.fr

Neutron diffraction is a well developed technique with many applications in all fields of the solid state sciences. It is perfectly adapted to crystallographic studies in a complementary way to X-ray diffraction. The particular properties of neutrons, compared to X-rays, make them the probe of choice to refine the position and occupation factors of light elements in crystalline materials (i.e. hydrogen in intermetallic compounds), to distinguish adjacent elements in the periodic table, to determine magnetic structures, to study all kind of phase transitions in complex environment, etc.

The Institute Laue-Langevin is currently under a process of upgrading many existing instruments and constructing new ones. The Millennium Program is under strong development and diffraction instruments play an important role in it. In this talk, after reviewing the most important characteristics of neutron diffraction, I will present the current situation at ILL concerning diffraction, particularly the upgrades of the high resolution powder diffractometer D2B, the high resolution mode of D20 and the single crystal diffractometers D10 and D19 as well as the new proposed diffractometer DRACULA. Some words will be devoted to the quasi-Laue diffractometers VIVALDI, ORIENT EXPRESS and the new project CYCLOPS. I will also describe the existing projects concerning the development of software for data analysis related to the high throughput of the new instruments.

As an illustration of the present capabilities of the existing instrument, in comparison with other neutron sources in the world, I will present some neutron powder diffraction examples.