Depth-dependent magnetic correlation length in terbium (abstract)
- Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)
- Department of Physics, Brookhaven National Laboratory, Upton, New York 11973 (United States)
High [ital q]-resolution neutron-scattering measurements of the critical scattering in Tb above the magnetic-spiral phase transition temperature [ital T][sub [ital s]] exhibit a two-component line shape, as recently documented in Ho.[sup 1] This implies the existence of a second length scale, which runs counter to our present understanding of second order phase transitions. By using a narrow beam only 300 [mu]m wide, and then translating the crystal through the beam, we have established that the origin of the second length scale lies within the near surface volume or skin'' of the Tb crystal.[sup 2] This is manifested by a large enhancement of the scattering intensity at the [ital c]-axis face of the cube-shaped crystal. In this context the meaning of skin is distinct from that of surface since the second component is spread over several hundred micrometers and not just one or two. In addition, we find that not all skins are equivalent. The intensity of the second component scattering is greatest in those faces that are orthogonal to the [ital c]-axis face. Such an anisotropy is easily motivated on physical grounds given that the spins in Tb are confined to the basal plane below [ital T][sub [ital s]].
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 7284272
- Journal Information:
- Journal of Applied Physics; (United States), Vol. 75:10; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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