Temperature and polarization dependence of Fe L3-edge X-ray absorption spectra of LuFe2O4

- We have measured the Fe L2,3 XAS were measured at the temperature range of 7-573 K.
- We found the polarization dependence of XAS revealed that the energy level of (dxy, dx2-y2) was lower than that of (dyz, dzx).
- We observed the Fe2+ and Fe3+ are kept even at higher temperatures.

The charge ordering of Fe2+ and Fe3+ ions in LuFe2O4 induces ferroelectricity below 330 K. In this study, the X-ray absorption spectra (XAS) at the Fe L2,3-edge are investigated to study charge ordered- and disordered-states. The polarization dependence of XAS revealed that the energy level of (dxy, dx2-y2) is lower than that of (dyz, dzx). In the charge-ordered state, the Fe L3-XAS shows a double-peak structure, which is a characteristic of Fe2+ and Fe3+ ions. In the high-temperature region, the double-peak structure becomes a broad single peak, because of overlap with the thermally excited state.