Polarized neutron study of the magnetization density distribution within a CoFe/sub 2/O/sub 4/ colloidal particle (magnetization density in a colloidal CoFe/sub 2/O/sub 4/ crystallite) [electronic resource].
- Kingston, R.I. : University of Rhode Island, 1983. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
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- Pages: 12 : digital, PDF file
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- University of Rhode Island and United States. Department of Energy. Office of Scientific and Technical Information
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- Free-to-read Unrestricted online access
- Magnetization and Moessbauer data suggest that a magnetically anomalous region exists within finely divided CoFe/sub 2/O/sub 4/ particles when coated with oleic acid. We have undertaken an x-ray and a polarized neutron powder diffraction study of these samples with and without the surfactant coating in an attempt to locate and characterize this anomalous zone. The shape of neutron scans of the (4,0,0) reflection are independent of polarization indicating that the reflecting crystallites are uniformly magnetized. Magnetization calculated from the peak flipping ratio is characteristic of uncoated rather than coated particles in both cases. Scan widths of both x-rays and neutrons are narrower for the sample from which the chemisorbed surfactant has been largely removed indicating an increase in the size of the coherent lattice of a crystallite. These observations are consistent with the existence of a highly strained surface layer roughly 10 Angstroms thick characterized by pinned spins associated with the presence of oleic acid, which relaxes to a more normal lattice structure upon boiling off the surfactant.
- Published through SciTech Connect., 01/01/1983., "bnl-32685", " conf-830619-1", "DE83010015", 3. international conference on magnetic fluids, Bangor, UK, 28 Jun 1983., and Berkowitz, A.E.; Majkrzak, C.F.; Nunes, A.C.
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