Mossbauer57Fe spectra from the intermetallic compounds PuFe2, NpFe2and UFe2

Abstract

Using the isotope ⁵⁷Fe, a Mossbauer study of the three Laves phase compounds PuFe₂, NpFe₂, UFe₂ has been made at helium (4K), nitrogen (77K) and room temperatures. Both PuFe₂ and NpFe₂ exhibit magnetic splitting at room temperature, but UFe₂ displays only a quadrupole pair. This material has a Curie temperature of 195K, and magnetic splitting is seen in the nitrogen and helium spectra. It is deduced that for these three materials in the spin-ordered state the hyperfine magnetic field points in a (111) direction, and that the magnetic spectra consist of two eight-line contributions, though the less intense lines are not resolved.