Pressure-induced charge orders and their postulated coupling to magnetism in hexagonal multiferroic LuFe2O4

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) propa...

Three-dimensional magnetic correlations in multiferroic LuFe2O4.

We present single crystal neutron diffraction measurements on multiferroic LuFe(2)O(4). Magnetic reflections are observed below transitions at 240 and 175 K indicating that the magnetic interactions in LuFe(2)O(4) are three-dimensional in character. The magnetic structure is refined as a ferrimagnetic spin configuration below the 240 K transition. Below 175 K a significant broadening of the mag...

High - pressure structural stability of multiferroic hexagonal

P. Gao,1 Z. Chen,1 T. A. Tyson,1,2 T. Wu,1 K. H. Ahn,1,2 Z. Liu,3 R. Tappero,4 S. B. Kim,2 and S.-W. Cheong2 1Department of Physics, New Jersey Institute of Technology, Newark, New Jersey 07102, USA 2Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA 3Geophysical Laboratory, Carnegie Institution of Washington, D.C...

Direct observation of charge order and an orbital glass state in multiferroic LuFe2O4.

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 ...

Intrinsic defects in multiferroic BiFeO3 and their effect on magnetism