Spin Fluctuations in Plutonium and Other Actinide Metals and Compounds

Abstract

It is proposed that the anomalous behavior of the resistivities of Pu and Np and some actinide intermetallic compounds can be explained on the basis of spin fluctuations in narrow $5f$ bands. An initial ${T}^{2}$ increase is observed in the resistivities of all these systems. From radiation-damage data we conclude that there are two distinct regions of $5f$-electron behavior: (i) a high-temperature region (\ensuremath{\gtrsim} 100 \ifmmode^\circ\else\textdegree\fi{}K), where the $5f$ electrons occupy virtual bound states and the metal resembles a disordered alloy with magnetic impurities such as Pd(U), and (ii) a low-temperature region, where the $5f$ bands are hybridized and a well-defined Fermi surface is formed. Anomalies observed in several properties of Pu at 60 \ifmmode^\circ\else\textdegree\fi{}K may well reflect the temperature at which well-defined $5f$ bands begin to form.