Field-induced-magnetic-moment form factor of metallic chromium

Polarized-neutron techniques have been used to study the spatial distribution and temperature dependence of the field-induced magnetic moment in metallic chromium. It is demonstrated that the coherent magnetic scattering of neutrons by the induced magnetic moment in chromium may be described in terms of free-ion form factors. The angular distribution of the magnetic scattering is best fitted by having a 60% $3d$ orbital-40% $3d$ spin contribution to the induced moment both above and below the antiferromagnetic transition temperature of the sample. The orbital and spin contribution to the static susceptibility were found to be (98 ± 3) × ${10}^{-6\mathrm{}}$ emu/mol and (65 ± 2) × ${10}^{-6\mathrm{}}$ emu/mol, respectively; the gyromagnetic ratio is 1.25 ± 0.04. These results are in good agreement with bulk-susceptibility measurements performed on the same sample, as well as with independent measurements of the gyromagnetic ratio of chromium. The magnitude of the localized induced moment has been found to be temperature independent in the (27-200)°C temperature region. This result implies the absence of any well-defined local moment above the antiferromagnetic transition temperature of the sample.