Determination of the magnetization distribution in Cr2O3 using spherical neutron polarimetry

The magnetization distribution due to the Cr3+ ion in Cr2O3 has been determined using spherical neutron polarimetry. The magnetic structure factors of h 0 l reflections have been measured out to sin θ/λ = 0.75 A-1. The results show that the Cr3+ magnetic moment is reduced by the zero-point spin deviation and by covalent mixing to 2.48 µB. They are consistent with the Cr d electrons being in the trigonally symmetric a1 and e orbitals derived from the cubic orbitals with t2g symmetry. There is a small but significant magnetization which is not accounted for by these orbitals, which is attributed to covalent overlap. Its symmetry is consistent with the magneto-electric susceptibility.