Reference : Spin structure of nanocrystalline terbium
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Physics
http://hdl.handle.net/10993/603
Spin structure of nanocrystalline terbium
English
Weissmüller, J. [> >]
Michels, Andreas mailto [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit >]
Michels, D. [> >]
Wiedenmann, A. [> >]
Krill III, C. E. [> >]
Sauer, H. M. [> >]
Birringer, R. [> >]
2004
Physical Review. B, Condensed Matter and Materials Physics
American Physical Society
69
0544021-05440216
Yes (verified by ORBilu)
1098-0121
1550-235X
Woodbury
NY
[en] We present an experimental study of the magnetic microstructure in the nanocrystalline hard magnet Tb. Field-dependent small-angle neutron scattering (SANS) data are analyzed quantitatively in terms of the correlation function of the spin misalignment. We find that up to applied fields of several tesla the magnetization remains “locked in” to the basal planes of the hcp crystal lattice of each individual crystallite, but that the in-plane orientation of the spins is highly nonuniform within each grain. This spin disorder at the nanoscale can be suppressed by a large applied field, but in the remanent state the disorder reduces the magnetization to values considerably below the Stoner limit. In field-dependent SANS, the intragrain spin disorder gives rise to a crossover of the scattering curves, and to the unusual finding that the scattering cross section at small scattering vector increases with increasing magnetic field. As the origin of the internal spin disorder within the grains, we propose an extra magnetic anisotropy energy at small grain size, presumably due to microstrain, a suggestion which is supported by analysis of ac-susceptibility data in the paramagnetic state. Our finding of a reduced remanence at small grain size is contrary to the remanence enhancement that is observed in other nanocrystalline hard magnets. We also report an unusual logarithmic field dependence of the magnetization over wide ranges of the applied field and temperature.
http://hdl.handle.net/10993/603
10.1103/PhysRevB.69.054402

File(s) associated to this reference

Fulltext file(s):

FileCommentaryVersionSizeAccess
Limited access
Weissm_PRB_2004.pdfPublisher postprint512.79 kBRequest a copy

Bookmark and Share SFX Query

All documents in ORBilu are protected by a user license.