Relevance of Kondo physics for the temperature dependence of the bulk modulus in plutonium.

The recent PNAS paper by Migliori et al. (1) attempts to explain the unusually strong temperature dependence of the bulk modulus of fcc plutonium (δ-Pu) by use of the disordered local moment (DLM) model. It is our opinion that this approach does not correctly incorporate the dynamic magnetism of δ-Pu. First, we note that, contrary to the comments in Migliori et al. (1), the results of our recent inelastic neutron experiments (2) do not contradict the results of earlier experiments (3⇓–5), which show that the ground state is nonmagnetic. All of these experiments are consistent with the interpretation that δ-Pu has a nonmagnetic fluctuating valence ground state. …