MAGNETISM AND NEUTRON POWDER DIFFRACTION. F. Bourée, Laboratoire Lon Brillouin (CEA-CNRS), CEA/Saclay,F-91191 Gif-sur-Yvette

Magnetic structure determination (description of the microscopic arrangement of magnetic moments in a crystal) requires neutron diffraction studies. Magnetic neutron powder diffraction is, and will remain in the future, the most straightforward technique to get magnetic structures as a function of temperature. We will show here the successive steps of a magnetic structure determination, from the experiment (2-axis diffractometer, sample environment) to the results: commensurate and/or incommensurate long-range magnetic order, via data analysis (Rietveld profile refinement). Some examples are selected, in RT₂X₂, R₂T₂X and AB₂O₄ systems (with R= Lanthanide or Uranium; T, A, B=Transition Metal, X=Si, Ge, In or Sn).