
electrons, or large magnetocrystalline anisotropy of
interfaces. As the scattered signals are of nuclear or
magnetic origin, or both, the effectiveness of mag-
netic reflectometry takes advantage of polarized neu-
tron beams and polarization analysis techniques.
3. Conclusion
Scattering methods using thermal neutrons are par-
ticularly well suited to deliver unique information on
magnetic materials, and more particularly on those
expected to show potential as high-performance mag-
nets. Such magnetic materials are composed of tran-
sition and rare-earth metals, but often also contain
further elements in rather small amounts. The large
dimensional range (from electrons or orbitals to mi-
cro- and centimeter scales) can be treated using a very
wide range of powerful techniques. This allows not
only the characterization of static parameters, but
also of dynamics and excitation phenomena, thus ef-
fectively providing typical energies. Both aspects are
associated with the intrinsic quantities, such as mag-
netization, exchange forces, and CEF strengths.
Many extrinsic but critical quantities can also be
analyzed, especially those being relevant for chemical
procedures, processes, microstructure optimization,
etc. The multipurpose neutron scattering techniques
as such have no equivalent, especially because of their
efficiency in depth penetration, contrary to x-ray
techniques. Owing to the increasing neutron fluxes
and to the correspondingly improved detection tech-
niques, more and more detailed information can be
obtained. Hence, either microintegrated materials or
microstructured functional materials can be investi-
gated to satisfy the interest in these materials. It can
be very fruitful to combine the neutron investigation
methods as described here with more conventional,
laboratory-scale techniques to support the produc-
tion of new, hard magnetic materials.
See also: Crystal Field Effects in Intermetallic
Compounds: Inelastic Neutron Scattering Results;
Magnetic Excitations in Solids
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D. Fruchart
Laboratoire de Cristallographie du CNRS, Grenoble
France
1023
Permanent Magnet Materials: Neutron Experiments