1027 K
17 pp.
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TitlePolarized Neutron Studies on Antiferromagnetic Single Crystals: Technical Report No. 4
Author(s)Nathans, R.; Riste, T.; Shirane, G.; Shull, C.G.
Publication DateNovember 26, 1958
Report NumberAFOSR-TR-58-1058
Unique IdentifierACC0097
Other NumbersAD-206986; OSTI ID: 4291138
Research OrgMassachusetts Inst. of Tech., Cambridge. Structure of Solids Group and Brookhaven National Laboratory, Upton, N.Y.
Contract NoAF 18(603)-84
Sponsoring OrgUS Atomic Energy Commission (AEC); National Security Agency; and Air Force Office of Scientific Research (AFOSR)
SubjectPhysics and Mathematics; Chromium Oxides; Ferromagnetic Materials; Iron Oxides; Lattices; Magnetic Fields; Magnetic Materials; Magnetic Moments; Measured Values; Monocrystals; Neutron Beams; Neutrons; Polarization; Reflection; Scattering; Temperature; Thermal Neutrons
KeywordsChromium Oxides; Neutron Scattering; Iron(III) Oxides; Neutrons; Polarization; Neutron Polarization Studies on Antiferromagnetic Crystals
Related Web PagesClifford Shull, Neutron Diffraction, and Neutron Scattering
AbstractThe theory of neutron scattering by magnetic crystals as given by Halpern and Johnson predicts changes in the polarization state of the neutron beam upon scattering which depend upon the relative orientation of the neutron polarization vector and the crystal magnetic axis. This was investigated experimentally with a polarized beam spectrometer using single crystals of Cr{sub 2}O{sub 3} and alpha - Fe{sub 2}O{sub 3} in which reside unique antiferromagnetic axes. Studies were made on several different reflections in both crystals for a number of different temperatures both below and above the Neel point. Results support the theoretical predictions and indicate directions for the moments in these crystals consistent with previous work. A more detailed study of the polarization changes in the (111) reflection in alpha - Fe{sub 2}O{sub 3} at room temperature on application of a magnetic field was carried out, The results indicate that the principal source of the parasitic ferromagnetism in hematite is essentially independent of the orientation of the antiferromagnetic domains within the crystal.
1027 K
17 pp.
View Document 

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