Charge order in LuFe2O4: antiferroelectric ground state and coupling to magnetism.
X-ray scattering by multiferroic LuFe2O4 is reported. Below 320 K, superstructure reflections indicate an incommensurate charge order with propagation close to (1/3 1/3 3/2). The corresponding charge configuration, also found by electronic structure calculations as most stable, contains polar Fe/O double layers with antiferroelectric stacking. Diffuse scattering at 360 K, with (1/3 1/3 0) propagation, indicates ferroelectric short-range correlations between neighboring double layers. The temperature dependence of the incommensuration indicates that charge order and magnetism are coupled.
Angst
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M
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA. m.angst@fz-juelich.de
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