We report experimental evidence for the charge-orbital ordering in magnetite below the Verwey transition temperature TV. Measurements of O K-edge resonant x-ray scattering on magnetite reveal that the O 2p states in the vicinity of the Fermi level exhibit a charge-orbital ordering along the c axis with a spatial periodicity of the doubled lattice parameter of the undistorted cubic phase. Such a charge-orbital ordering vanishes abruptly above TV and exhibits a thermal hysteresis, correlating closely with the Verwey transition in magnetite.
