Local electronic structure of Fe2+ impurities in MgO thin films: Temperature-dependent soft x-ray absorption spectroscopy study

Article

关键词: VERWEY TRANSITION;    LATTICE-DYNAMICS;    MAGNETITE FE3O4;    SPECTRA;    PHOTOEMISSION;    MGO-FE2+;    BEAMLINE;    LEVEL;    3D;   

DOI  :  10.1103/PhysRevB.82.035120

来源: SCIE

【 摘 要 】

We report on the local electronic structure of Fe impurities in MgO thin films. Using soft x-ray absorption spectroscopy, we verified that the Fe impurities are all in the 2+ valence state. The fine details in the line shape of the Fe L-2,L-3 edges provide direct evidence for the presence of a dynamical Jahn-Teller distortion. We are able to determine the magnitude of the effective D-4h crystal field energies. We also observed a strong temperature dependence in the spectra which we can attribute to the thermal population of low-lying excited states that are present due to the spin-orbit coupling in the Fe 3d. Using this Fe2+ impurity system as an example, we show that an accurate measurement of the orbital moment in Fe3O4 will provide a direct estimate for the effective local low-symmetry crystal fields on the Fe2+ sites, important for the theoretical modeling of the formation of orbital ordering.

【 授权许可】

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