https://doi.org/10.1140/epjp/s13360-023-04449-5
Regular Article
Lanthanide exchange fields and intermultiplet transitions in permanent-magnet materials
1
IM2NP-CNRS UMR 7334, Aix-Marseille Université, Campus St. Jérôme, Case 142, 13397, Marseille, France
2
Leibniz IFW Dresden, Helmholtzstr. 20, 01069, Dresden, Germany
3
TU Dresden, Dresden Center for Computational Materials Science (DCMS), 01062, Dresden, Germany
Received:
30
June
2023
Accepted:
4
September
2023
Published online:
30
November
2023
Intermultiplet (spin-orbit) transitions in lanthanides, observed by means of high-energy inelastic neutron scattering are well-suited for the determination of exchange field 
in permanent-magnet materials. The situation is particularly favorable in Nd-based magnets, where is given by 
, 
being the observed transition energy and 
the spin-orbit splitting between the barycenters of the two lowest-lying multiplets. The latter can be regarded as a known atomic constant, 
meV. A more accurate value of is obtainable by way of relativistic density-functional calculations, however, it proves material-dependent. Thus, 
meV for Nd
Fe
B. Two obstacles in the way of the direct determination of are J-mixing and crystal electric field. In order to allow for the J-mixing, approximate formulas are proposed that enable a definitive solution of the problem. By contrast, crystal-field corrections have to be treated on a case-by-case basis.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
