title: Charge order superstructure with integer iron valence in Fe(2)OBO(3).
abstract: Solution-grown single crystals of Fe(2)OBO(3) were characterized by specific heat, Mössbauer spectroscopy, and x-ray diffraction. A peak in the specific heat at 340 K indicates the onset of charge order. Evidence for a doubling of the unit cell at low temperature is presented. Combining structural refinement of diffraction data and Mössbauer spectra, domains with diagonal charge order are established. Bond-valence-sum analysis indicates integer valence states of the Fe ions in the charge ordered phase, suggesting Fe(2)OBO(3) is the clearest example of ionic charge order so far.
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA. angst@ornl.gov
authors.forename: M
authors.initials: M
authors.lastname: Angst
authors.forename: P
authors.initials: P
authors.lastname: Khalifah
authors.forename: R P
authors.initials: RP
authors.lastname: Hermann
authors.forename: H J
authors.initials: HJ
authors.lastname: Xiang
authors.forename: M-H
authors.initials: MH
authors.lastname: Whangbo
authors.forename: V
authors.initials: V
authors.lastname: Varadarajan
authors.forename: J W
authors.initials: JW
authors.lastname: Brill
authors.forename: B C
authors.initials: BC
authors.lastname: Sales
authors.forename: D
authors.initials: D
authors.lastname: Mandrus
mesh_terms: D007501:Iron / Q000737:chemistry; D015204:Spectroscopy, Mossbauer; D014961:X-Ray Diffraction
chemical_list: D007501:Iron