NEUTRON POWDER DIFFRACTION AND OXIDE SUPERCONDUCTORS

Neutron powder diffraction has been essential for understanding the st ructures of the new high temperature oxide superconductors because of the difficulty in locating oxygen with X-rays in the presence of heavy metals, especially when single crystals are usually not available. Th is understanding lead to the discovery of new materials. In this paper we will show how it also sheds light on the crystal chemistry of oxid e superconductors - the effects of oxidation/reduction, phase separati on, pressure etc.