Enhanced Coulomb and exchange interaction crystal fields in the modified Zener model of magnons in metallic ferromagnets

The Bartel treatment of magnons in metallic ferromagnets within the modified Zener model of itinerant-localized (s-electron or hole) exchange is generalized to include ten-fold d-electron (hole) spin-orbital degeneracy. As such one can ab initio include enhanced intra-cell Coulomb repulsive crystal fields and exchange attractive crystal fields. This treatment includes itinerant-itinerant (d-electron or hole) Coulomb and exchange interactions as well as itinerant-localized (d-electron or hole) interactions; Hund's rule coupling is included automatically. Also, ab initio the ferromagnet specificity is included via the d-bandfilling and d-bandwidth inherent in the degenerate theory; the possibility of finite temperatures is also included. Acoustic and optic ferromagnon branches are recalculated and corrected and the position of the Stoner particle-hole continuum boundary is recalculated at zero and finite temperatures.