Compared are recent EPR, susceptibility, and neutron measurements of both S-state (b40) and non-S-state (A40r4) lanthanide-ion crystal-field splittings in metals. The ratio of the S-state to the non-S-state fields R=b40A40r4 in some metals is anomalously large and cannot be explained by the current insulator theory. We suggest that there must exist an extra "metallic" contribution to both A40r4 and the ratio R. The non-S-state field A40r4 is divided into two: (i) all Coulombic and exchange contributions, and (ii) a covalent contribution similar to that found in insulators. We show that the latter term is more efficient in its contribution to the S-state field b40. We suggest, in the anomalous metals, the S state b40 is dominated by covalent mixing but that for the non-S-state ions there is a partial cancellation between covalent and the coulomb-field contributions. Finally the implications for the Gd3+, 4f7 to 4f8 interconfigurational energy are explained.
ASJC Scopus subject areas
- Condensed Matter Physics