References of "Michels, D"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailSpin structure of nanocrystalline terbium
Weissmüller, J.; Michels, Andreas UL; Michels, D. et al

in Physical Review. B, Condensed Matter and Materials Physics (2004), 69

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 ... [more ▼]

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. [less ▲]

Detailed reference viewed: 75 (0 UL)
Full Text
Peer Reviewed
See detailMagnetic microstructure and properties of the nanocrystalline hard magnet terbium
Weissmüller, J.; Michels, D.; Michels, Andreas UL et al

in Physica Status Solidi A. Applied Research (2002), 189

We present an experimental study of the magnetic properties and magnetic microstructure in the nanocrystalline hard magnet Tb. Field-dependent small-angle neutron scattering (SANS) data suggest that up to ... [more ▼]

We present an experimental study of the magnetic properties and magnetic microstructure in the nanocrystalline hard magnet Tb. Field-dependent small-angle neutron scattering (SANS) data suggest 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; as a consequence, domain-wall movement along the basal planes is eliminated as a mechanism for magnetization reversal, and the coercive field is substantially increased. [less ▲]

Detailed reference viewed: 79 (1 UL)
Full Text
Peer Reviewed
See detailTomographic characterization of grain-size correlations in polycrystalline Al-Sn
Krill III, C. E.; Döbrich, K. M.; Michels, D. et al

in Developments in X-Ray Tomography III (2002)

Detailed reference viewed: 79 (4 UL)
Full Text
Peer Reviewed
See detailTomography with high resolution
Rau, C.; Weitkamp, T.; Snigirev, A. et al

in Developments in X-Ray Tomography III (2002)

Detailed reference viewed: 64 (5 UL)
Full Text
Peer Reviewed
See detailMagnetic small-angle neutron scattering by nanocrystalline terbium
Weissmüller, J.; Michels, D.; Michels, Andreas UL et al

in Scripta Materialia (2001), 44(8), 2357-2361

We present an experimental study of the magnetic microstructure in the nanocrystalline hard magnet Tb. Field-dependent SANS data are analyzed quantitatively in terms of the correlation function of the ... [more ▼]

We present an experimental study of the magnetic microstructure in the nanocrystalline hard magnet Tb. Field-dependent 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 particle. This internal structure can be suppressed by the applied field. [less ▲]

Detailed reference viewed: 80 (1 UL)