Neutron diffraction study of PuP: The electronic ground state

The neutron elastic magnetic cross section has been measured from ferromagnetic ²⁴²PuP at 4.2 K. As a result of the partial cancellation of →S and →L in the f⁵ state, the cross section is independent of angle for sinθλ<0.35 ^-1. A detailed analysis, including the effects of intermediate coupling and J mixing, allows an identification of the electronic ground state. The conduction-electron polarization (~0.35μB) is antiparallel to, and almost half the magnitude of, the localized $5f$ moment (0.77μB).