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The effect of Mg doping on the structural and physical properties of LuFe(2)O(4) and Lu(2)Fe(3)O(7)
1Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
Abstract:
The structural and physical properties of the recently discovered electronic ferroelectric materials LuFe(2)O(4) and Lu(2)Fe(3)O(7) have been investigated for Mg substitution of Fe. X-ray diffraction data demonstrate that the lattice parameters in both systems change progressively with increasing Mg content, with a smaller unit cell volume on replacing Fe(2+) by Mg(2+). X-ray absorption near-edge spectroscopy experiments at the Fe K-edge show that the average Fe oxidation state is slightly increased along with Mg doping in Lu(2)Fe(3)O(7) materials, consistent with isomorphous replacement of Fe(2+) by Mg(2+). Measurements of dielectric properties demonstrate that Mg doping could have an effect on the electron hopping energy between Fe(2+) and Fe(3+) ions. Transmission electron microscopy and magnetization analysis reveal that Mg doping in LuFe(2)O(4) has a much greater influence than in Lu(2)Fe(3)O(7) on both the charge ordering and the low-temperature magnetic properties.
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