Charge order superstructure with integer iron valence in Fe(2)OBO(3).
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.
Angst
M
M
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA. angst@ornl.gov
Khalifah
P
P
Hermann
R P
RP
Xiang
H J
HJ
Whangbo
M-H
MH
Varadarajan
V
V
Brill
J W
JW
Sales
B C
BC
Mandrus
D
D
D007501:Iron / Q000737:chemistry; D015204:Spectroscopy, Mossbauer; D014961:X-Ray Diffraction
D007501:Iron