An EELS study of near edge structures of the oxygen K-edge in spinels |
| |
| Authors: | Susanne Nyquist Ulf Hålenius |
| |
| Institution: | 1. Department of Physics, Stockholm University, 106 91, Stockholm, Sweden
2. Department of Geosciences, Swedish Museum of Natural History, 50007, 104 05, Stockholm, Sweden
|
| |
| Abstract: | Spectra of seven aluminate, ferrite and chromate spinels were collected at the oxygen K-edge in order to examine the effect of octahedral ion composition on the near edge structures and explore whether these may shed some light on previously reported major variations in the optical absorption coefficient (ε) for the spin-allowed d–d band transitions due to tetrahedrally coordinated Fe2+ in optical spectra of oxide spinels. Interpretation of the energy loss near edge structure (ELNES) spectra was aided using the multiple scattering code FEFF8.40. For the chromate samples spin polarised calculations were included. Gold’s iterative deconvolution method was utilized to improve on energy resolution, resulting in spectra equal in merit to those recorded by technically superior instruments. Results include absolute energy positions and interpretation of ELNES features in terms of transitions to available states. We conclude that the major causes of differences in the optical absorption coefficient mentioned above are hybridization between oxygen p- and octahedral metal orbitals. Our study does not support the idea presented by other authors that there exists a local antiferromagnetic ordering in MgCr2O4 at room temperature. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
