Spin and orbital moments inU3X4-type pnictides(X=P,As, Sb, Bi): Polarized neutron-diffraction study

Abstract

Polarized neutron experiments have been performed on single crystals of ${\mathrm{U}}_{3}{\mathrm{P}}_{4},$ ${\mathrm{U}}_{3}{\mathrm{As}}_{4},$ ${\mathrm{U}}_{3}{\mathrm{Sb}}_{4},$ and ${\mathrm{U}}_{3}{\mathrm{Bi}}_{4}.$ The spin and orbital components of the magnetic moments on the uranium atoms were separated within the dipole magnetic form factor approximation and compared to the theoretical values. The ratio of these components indicates an important hybridization of $5f$-electron states with the conduction band for all four compounds. The hybridization estimated in this way differs significantly for two uranium sublattices in ${\mathrm{U}}_{3}{\mathrm{Sb}}_{4}.$