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International
Tables for Crystallography Volume C Mathematical, physical and chemical tables Edited by E. Prince © International Union of Crystallography 2006 |
International Tables for Crystallography (2006). Vol. C. ch. 2.8, pp. 124-125
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The strong contribution of electronic magnetic moments in materials to neutron diffraction [item (d) in Section 2.8.1![[link]](/graphics/greenarr.gif)
] makes magnetic neutron scattering a unique tool in determining magnetic structures on the unit-cell level. When a single-crystal specimen contains regions with different magnetic structures, i.e. magnetic domains or coexisting phases with different magnetic structures, they will be imaged because of the local variations in structure amplitude, and hence in diffracted intensity, they entail. Ferromagnetic domains can be imaged by neutron topography (Schlenker & Shull, 1973). This is of restricted value because so many other and more efficient techniques are available, albeit not for observations in the bulk. But neutron topography is the only method available to visualize antiferromagnetic domains of various kinds. The pioneering work by Ando & Hosoya (1972, Ando & Hosoya, 1978) and Davidson, Werner & Arrott (1974) showed spin-density wave domains in antiferromagnetic chromium. Chirality domains (right/left-handed helix in helimagnets), as well as 180° antiferromagnetic domains, could also be observed for the first time using polarized neutron topography (Baruchel, Schlenker & Palmer, 1990). Neutron topography is also a valuable tool in the investigation of the coexistence of different magnetic phases, for example heli- and ferromagnetic, at a first-order phase transition, which can be driven either by temperature changes or by applying a magnetic field (Baruchel, 1989).
References
Ando, M. & Hosoya, S. (1972). Q-switch and polarization domains in antiferromagnetic chromium observed with neutron diffraction topography. Phys. Rev. Lett. 29, 281–285.Google Scholar
Ando, M. & Hosoya, S. (1978). Size and behavior of antiferromagnetic domains in Cr directly observed with X-ray and neutron topography. J. Appl. Phys. 49, 6045–6051.Google Scholar
Baruchel, J. (1989). The contribution of neutron and synchrotron radiation topography to the investigation of first-order magnetic phase transitions. Phase Transit. 14, 21–29.Google Scholar
Baruchel, J., Schlenker, M. & Palmer, S. B. (1990). Neutron diffraction topographic investigations of `exotic' magnetic domains. Nondestr. Test. Eval. 5, 349–367.Google Scholar
Davidson, J. B., Werner, S. & Arrott, A. S. (1974). Neutron microscopy of spin density wave domains in chromium. AIP Conf. Proc., edited by C. D. Graham & J. J. Rhyne, Vol. 18, pp. 396–400.Google Scholar
Schlenker, M. & Shull, C. G. (1973). Polarized neutron techniques for the observation of ferromagnetic domains. J. Appl. Phys. 44, 4181–4184.Google Scholar
