Spatial distribution of magnetization in the anisotropic Co(H₂O)²⁺₆ ion from polarized neutron diffraction

Abstract

In a polarized neutron diffraction experiment on the magnetically highly anisotropic ammonium cobalt Tutton salt (ND₄)₂Co(SO₄)₂·6D₂O, 70 and 22 flipping ratios were measured in the hk0 and h01 zones respectively. These, and the underlying magnetization distribution around Co, more closely resemble those predicted by a model with a cubic crystal field with CoO₆ axes, than those predicted from a generally orientated ellipsoidal crystal field, even though the latter provides a good fit to ESR and magnetic susceptibility data. However, all the real space magnetization distributions are substantially isotropic. For an examination of covalence as the experimental objective, these results indicate that a suitably scaled spin-only model for the magnetization distribution on the metal may suffice, even in highly anisotropic situations where a large orbital moment is present, such as the present case.