Polarized neutron-diffraction study of spin-density distribution in chromium tribromide

The distribution of magnetization in the insulating ferromagnet CrBr₃ has been studied using polarized and unpolarized neutron scattering. The magnetic scattering, modeled by a suitable wave function, is consistent with the crystal-field parameters from spectroscopic data. Calculations of the magnetic structure factors using suitable molecular-orbital functions showed that the 3d moment of 2.83μB on the chromium, larger than expected for a simple covalent transfer of moment to the ligands, as well as other features, was partly accounted for by exchange polarization of the doubly occupied bonding orbitals.