EELS analysis of cation valence states and oxygen vacancies in magnetic oxides

Transition metal oxides are a class of materials that are vitally important for developing new materials with functionality and smartness. The unique properties of these materials are related to the presence of elements with mixed valences of transition elements. Electron energy-loss spectroscopy (E ELS) in the transmission electron microscope is a powerful technique for me asuring the valences of some transition metal elements of practical importa nce, This paper reports our current progress in applying EELS for quantitat ive determination of Mn and Co valences in magnetic oxides, including valen ce state transition, quantification of oxygen vacancies, refinement of crys tal structures, and identification of the structure of nanoparticles. (C) 2 000 Elsevier Science Ltd. All rights reserved.