Evolution of charge order through the magnetic phase transition of LuFe2O4

Abstract

The charge order in multiferroic LuFe(2)O(4) has been investigated with resonant x-ray diffraction at the Fe K edge in the combined charge ordered and magnetic phase. The energy dependence of the charge order reflection (1/3 1/3 7/2) has been analyzed in detail to investigate the charge disproportionation between the iron sites as a function of temperature. It is found that the charge disproportionation is constant within 0.02e across the Neel temperature T(N). The charge order reflection exhibits a decrease in intensity with increasing temperature which is attributed to an increase in the probability of electron hopping. We confirm the increase in polarization at T(N) is not of static origin but rather dynamic. Our observations are consistent with antiferromagnetically aligned magnetic moments inhibiting the double exchange mechanism and reducing the probability of electrons hopping between Fe(2+) and Fe(3+) in the magnetic phase. © 2012, American Physical Society.