Magnetic Ordering and the Electronic Properties of the Heavy Rare-Earth Metals

The magnetic perturbation of the conduction-electron bands due to the periodic (and ferromagnetic) arrays of $4f$ moments, occurring in the heavy rare-earth metals, has been estimated from nonrelativistic augmented-plane-wave energy-band results for Tm. The relationship between these perturbations, the ordering period, and other observables, such as the c-axis resistance anomalies, are inspected. Important to these considerations and to an understanding of the ordering of the $4f$ moments is the magnitude of the perturbation effects which result in sizable gaps relative to the bandwidth in the $5d$ bands, destroy large segments of Fermi surface (primarily normal to the c axis), and force appreciable redistributions of the populated conduction-electron states.