AbstractThe energy distributions of neutrons scattered by α‐MnSO4 and β‐MnSeO4 in their paramagnetic state are measured by means of a time‐of‐flight technique. From a simultaneous analysis of the second moment of these energy distributions and of the Néel temperature computed in the Green's function approximation it is concluded that the exchange interactions between fourth neighbours play an important role in these manganese compounds. Values for J1 and J4 are obtained from which reasonable values for Θ and χ(TN) are predicted in the case of α‐MnSO4.

Fe2P is reported to be ferromagnetic with an average magnetic moment of about 1.3 μB per iron atom. However, neutron diffraction measurements give two different values for the magnetic moments on both iron sites. This difference is significantly larger than those reported in the literature. The best fit with the neutron diffraction data is obtained for a magnetic moment of 0.69 μB on the tetragonal Fe [1] site and of 2.31 μB on the pyramidal Fe [2] site.

Fe 2 P is reported to be ferromagnetic with an average magnetic moment of about 1.3 μ B per iron atom. However, neutron diffraction measurements give two different values for the magnetic moments on both iron sites. This difference is significantly larger than those reported in the literature. The best fit with the neutron diffraction data is obtained for a magnetic moment of 0.69 μ B on the tetragonal Fe [1] site and of 2.31 μ B on the pyramidal Fe [2] site.

Low temperature neutron-diffraction measurements of FeOHSO4 show that the moments can be described by means of two wave vectors k1 [2π, 2π, 2π]. Magnetic intensities described by the [2π, 2π, 0] mode decrease slower with increasing temperature.

AbstractCo3O4 is a normal spinel with only A‐A interactions which becomes antiferromagnetic at TN ≈︁ 40 K. The exchange integrals between one ion and its first and second neighbours are derived from the second moment of energy distributions of neutrons scattered by a polycrystalline sample in its paramagnetic state (155 K) and from a Green's function analysis of TN. The result, J1/kB = −(7.27 ± 0.25) K and |J2|/kB < 0.3 K, indicates that the interaction with the nearest neighbours is by far dominant.

physica status solidi (b)Volume 70, Issue 1 p. K69-K72 Short Note Exchange Integral in Normal Spinels with only A-A Interactions D. Scheerlinck, D. Scheerlinck Solid State Physics Department, S. C. K./C. E. N., Mol WONL, Rijksuniversiteit Gent.Search for more papers by this authorS. Hautecler, S. Hautecler Neutron Physics Department, S. C. K./C. E. N., MolSearch for more papers by this authorW. Wegener, W. Wegener Neutron Physics Department, S. C. K./C. E. N., MolSearch for more papers by this author D. Scheerlinck, D. Scheerlinck Solid State Physics Department, S. C. K./C. E. N., Mol WONL, Rijksuniversiteit Gent.Search for more papers by this authorS. Hautecler, S. Hautecler Neutron Physics Department, S. C. K./C. E. N., MolSearch for more papers by this authorW. Wegener, W. Wegener Neutron Physics Department, S. C. K./C. E. N., MolSearch for more papers by this author First published: 1 July 1975 https://doi.org/10.1002/pssb.2220700160Citations: 3 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume70, Issue11 July 1975Pages K69-K72 RelatedInformation

AbstractThe energy distributions of neutrons scattered by Co3O4 in its paramagnetic state have been measured by means of a time‐of‐flight technique. In this normal spinel with only A‐A interactions, the JAA exchange integral has been derived from the second moment of these energy distributions. The result, JAA/kB = (7.27 ± 0.25) K, has been compared with values deduced from an analysis of the macroscopic magnetic data.

AbstractThe energy distributions of neutrons scattered by NiS04 in its paramagnetic state are measured by means of a time‐of‐flight technique. Restricting the range of the exchange interactions to the first and second nearest‐neighbours, the relation (J1/kB)2 + 2(J2/kB)2 = = (149±7) °K2 is obtained from the second moment of these energy distributions. A second relation between the two exchange parameters is obtained from a computation of the Néel temperature in the Green's function approximation. From the two relations J1/kB = = (8 ± 0.8) °K and J2/kB = (−6.5 ± 0.6) °K are derived. Taking properly into account a temperature‐independent contribution to the susceptibility, no experimental indication is found that there are other significant exchange interactions.

The room-temperature spin wave spectrum in MnFe2O4 has been investigated by means of inelastic neutron scattering using the time-of-flight technique. The acoustical branch could be obtained in the [100]- and the [110]-directions up to nearly the Brillouin zone boundary. Values for the effective exchange parameters JAB and JBB have been derived. In both symmetry directions some low lying phonon branches could also be observed.

The room-temperature spin wave spectrum has been investigated in Mn1.7Fe1.3O4 by means of inelastic neutron scattering. The acoustical branch could be obtained in the symmetry directions. Values for the effective exchange parameters JAR and JRR have been derived. Some acoustical phonon branches could also be observed and the elastic constants C44 and (C11 – C12) were estimated.