Effect of Pressure and Temperature on the Electrical Resistance of Eleven Rare-Earth Metals

The electrical resistance of eleven rare-earth metals has been measured as a function of pressure to over 500 kbars at 77 and 296^∘{}K. Appropriate isobars between 77 and 296^∘{}K have also been obtained. The electronic structure of rare-earth metals is complex with the $4f$ and $5d$ atomic levels relatively close, and both atomic levels split by the crystal field. A wide variety of transitions are observed, many of which must be electronic in character, i.e., they must involve the lowering in energy of one electronic energy band vis-\`a-vis another with increasing pressure and decreasing interatomic distance. These data should provide a partial basis for a theoretical treatment of energy bands in the rare-earth metals.