ELNES as a probe of magnetic order in mixed oxides

A previous study of chromite and ferrite spinels revealed energy-loss near-edge structure (ELNES) in the oxygen K-edge that could not be reproduced in non-spin polarised calculations. Chromite and ferrite spinels typically undergo transitions to long range ordered magnetic structures at temperatures below ∼15K. A model in which dynamic magnetic short range order (SRO) persists above the Neel temperature until 100K has been proposed using neutron powder diffraction. In the TEM, the interaction time of the fast electron with the specimen is sufficiently short for dynamic magnetic interactions to influence the observed ELNES at 300K. Here we present new spin polarised calculations performed using the commercially available codes FEFF8.2 and Wien97. The calculated oxygen K-edge ELNES show improved agreement with experiment when magnetic interactions are included in the calculation