INCOMMENSURATE CHARGE ORDERING IN MIXED-VALENCE SYSTEM LUFE2O4

Charge ordering of a mixed valence system LuFe2O4 has been studied by neutron scattering technique, focusing attention on the charge frustra tion effect on triangular lattice. It is revealed that the system unde rgoes successive phase transitions following the sequence of disorder --> two-dimensional charge density wave state (2D-CDW) --> three-dimen sional charge density wave state (3D-CDW). In 2D-CDW state, the charge density wave defined by the wave vector (1/3 1/3) is formed in the he xagonal layer. (C) 1998 Elsevier Science B.V. All rights reserved.