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White Lines and 3d-Occupancy for the 3d Transition-Metal Oxides

J. Graetz·C. C. Ahn·H. Ouyang·P. Rez·B. Fultz
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Abstract

Electron energy-loss spectrometry was employed to measure the white lines at the L23 absorption edges of the 3d transition-metal oxides and lithium transition-metal oxides. The white-line ratio (L3/L2) was found to increase between d^0 and d^5 and decrease between d^5 and d^10, consistent with previous results for the transition metals and their oxides. The intensities of the white lines, normalized to the post-edge background, are linear for the 3d transition-metal oxides and lithium transition-metal oxides. An empirical correlation between normalized white-line intensity and 3d occupancy is established. It provides a method for measuring changes in the 3d-state occupancy. As an example, this empirical relationship is used to measure changes in the transition-metal valences of Li_{1-x}Ni_{0.8}Co_{0.2}O_2 in the range of 0 < x < 0.64. In these experiments the 3d occupancy of the nickel ion decreased upon lithium deintercalation, while the cobalt valence remained constant.

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J. Graetz, C. C. Ahn, H. Ouyang, P. Rez, B. Fultz. 2004-06-23. White Lines and 3d-Occupancy for the 3d Transition-Metal Oxides. https://doi.org/10.1103/physrevb.69.235103

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