| Summary: | Samples of nonstoichiometric iron(II) oxide, FeyO, have been studied by polarized neutron diffraction, at 45 K, and Mössbauer spectroscopy, at 4.2 and 78 K. The neutron measurements, on samples of compositions Fe0.926O and Fe0.943O, show that antiferromagnetic order is maintained in the vicinity of defect clusters. In the intercluster region the spin direction is approximately 30° from [111], but close to the defects it is about 35° from the (111) plane. The spin structure is approximately collinear at the local level. The Mössbauer spectra of a sample of composition Fe0.918O are extremely complex. They have been fitted to a model involving one iron(III) hyperfine sextet, two iron(II) hyperfine sextets, and an iron(III) quadrupole doublet with a very large splitting (3.8 mm s-1). The doublet is ascribed to the iron(III) tetrahedral interstitials, which may be paramagnetic or spin paired with adjacent interstitials. © 1984 American Chemical Society.
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