Ce2Fe17: Mixed valence or 4<i>f</i> band?

Abstract

The Ce2Fe17 compound has a volume that is 4% smaller than expected for a localized 4f1 configuration of cerium. The Ce LIII absorption edge shows two peaks, at 5734 and 5740 eV. There is an extremely large linear term in the low-temperature specific heat, γ=560±100 mJ/mol K2. These results are discussed in terms of 4f0(Ce4+)↔4f1(Ce3+) valence fluctuations or a narrow 4f band at the Fermi level occupied by less than one 4f electron per cerium, where the heat capacity is enhanced by 4f quasiparticle formation.