THE THOMAS-FERMI LIMIT OF CRYSTAL-FIELD INTERACTION

Rare-earth permanent magnets are metals, and it is physically unreasonable to treat crystal-field generating charges as point charges. A more realistic description is given by the screened-charge model, where the conduction electrons are treated as linearized Thomas-Fermi gas. The distance dependence A(m)(n) proportional to 1/R(2m+1) of the point-charge model is replaced in the screened-charge model by spherical Bessel functions. An explicit description of these functions is given, and it discussed how Thomas-Fermi screening affects the rare-earth sublattice anisotropy of metallic permanent magnets.