Geometrical frustration of the Fe ions in LuFe2O4 leads to intricate charge and magnetic order and a strong magnetoelectric coupling. Using resonant x-ray diffraction at the Fe K edge, the anomalous scattering factors of both Fe sites are deduced from the (h/3 k/3 l/2) reflections. The chemical shift between the two types of Fe ions equals 4.0(1) eV corresponding to full charge separation into Fe2+ and Fe3+. The polarization and azimuthal angle dependence of the superlattice reflections demonstrate the absence of differences in anisotropic scattering revealing random orientations of the Fe2+ orbitals characteristic of an orbital glass state.

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Magnetic spiral structures can exhibit ferroelectric moments as recently demonstrated in various multiferroic materials. In such cases the helicity of the magnetic spiral is directly correlated with the direction of the ferroelectric moment and measurement of the helicity of magnetic structures is of current interest. Soft x-ray resonant diffraction is particularly advantageous because it combines element selectivity with a large magnetic cross-section. We calculate the polarization dependence of the resonant magnetic x-ray cross-section ͑electric dipole transition͒ for the basal plane magnetic spiral in hexaferrite Ba 0.8 Sr 1.2 Zn 2 Fe 12 O 22 and deduce its domain population using circular polarized incident radiation. We demonstrate there is a direct correlation between the diffracted radiation and the helicity of the magnetic spiral.Magnetic spiral structures can exhibit ferroelectric moments as recently demonstrated in various multiferroic materials. [1][2][3][4] In such cases the helicity of the magnetic spiral is directly correlated with the direction of the ferroelectric moment and measurement of the helicity of magnetic structures is of current interest. Magnetic spiral structures have been observed directly with neutron diffraction ͑ND͒ and resonant x-ray diffraction ͑RXD͒ 5 as their superstructure gives rise to satellite reflections. With polarized neutron diffraction the chirality of the magnetic structure can be determined, as was first predicted by Blume 6 and achieved by Siratori. 7 Recently this has been particularly insightful for the study of ferroelectric magnetic spiral structures in TbMnO 3 , 8 LiCu 2 O 2 , 9 and CuFe 1−x Al x O 2 10 observing that the chirality of the magnetic structure is manipulated with applied electric field. With circular polarized nonresonant x-ray diffraction the chiral magnetic domain population in holmium has been determined 11 and, very recently, polarization analysis has been used to study the cycloidal magnetic domains in multiferroic TbMnO 3 in its ferroelectric phase. 12 An advantage of RXD is that via tuning the incident energy to a particular absorption edge, element specific magnetism is observed. In the case of transition metals, the L 2,3 edge is particularly insightful because the core electron is excited from the core 2p to the 3d valence states and the ͑empty͒ magnetic states are directly probed. The magnetic cross-section is significant compared to the charge crosssection and soft x-ray resonant diffraction has emerged as a very valuable technique with which to study magnetic and orbital order in transition-metal oxides, in particular to distinguish between charge, orbital, and magnetic order. [13][14][15][16] Correlation between the RXD intensity and the helicity of the magnetic spiral has been demonstrated by imaging of the spiral domains in holmium 17 but a quantitative analysis of the diffracted intensities is missing.In this Brief Report we calculate the polarization dependence of the RXD cross-section and deduce the domain population of the magn...

We present a systematic study of the electronic structure in A-site ordered manganites as function of doping and temperature. The energy dependencies observed with soft x-ray resonant diffraction ͑SXRD͒ at the Mn L 2,3 edges are compared with structural investigations using neutron powder diffraction as well as with cluster calculations. The crystal structures obtained with neutron powder diffraction reflect the various orbital and charge ordered phases, and show an increase in the Mn-O-Mn bond angle as function of doping and temperature. Cluster calculations show that the observed spectral changes in SXRD as a function of doping are more pronounced than expected from an increase in bandwitdh due to the increase in Mn-O-Mn bond angle and are best described by holes that are distributed at the neighboring oxygen ions. These holes are not directly added to the Mn 3d shell but centered at the Mn site. In contrast, the spectral changes in SXRD as function of temperature are best described by an increase of magnetic correlations. This demonstrates the strong correlations between orbitals and magnetic moments of the 3d states.