Magnetic state of delta- and alpha-plutonium

Total energies of non-magnetic, ferromagnetic and antiferromagnetic phases of Pu in the fee structure (delta phase) have been calculated by the full-p otential linear augmented-plane-wave method. The antiferromagnetic solution (of the CuAu type) has been found as the most stable one. The ground-state equilibrium volume per atom agrees well with that of the low-temperature m onoclinic alpha phase. The latter includes 8 pairs of atoms per unit cell a nd resembles a frustrated body-centered tetragonal structure, making it log ical to assume the antiferromagnetic ordering related to the CuAu-type in t he fee structure for the alpha phase as well. Such magnetic solution has in deed been found, with magnetic moments not much different from those in the fee phase. (C) 2000 Elsevier Science B.V. All rights reserved.