Mulders AM, Lawrence SM, Staub U, Garcia-Fernandez M, Scagnoli V, Mazzoli C, Pomjakushina E, Conder K, Wang Y. Direct observation of charge order and an orbital glass state in multiferroic LuFe2O4.
PHYSICAL REVIEW LETTERS 2009;
103:077602. [PMID:
19792687 DOI:
10.1103/physrevlett.103.077602]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Indexed: 05/28/2023]
Abstract
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.
Collapse