Neutron diffraction and inelastic neutron scattering investigations of the ordered double perovskite Ba₂PrIrO₆

High-resolution neutron-powder diffraction data show that the double perovskite Ba₂PrIrO₆ is cubic at ambient temperatures in space group Fm over(3, -) m. Below T_N=71 K the compound orders antiferromagnetically with magnetic moments of ∼0.43(2) μ_B at 6 K, on both the Pr⁴⁺ and the Ir⁴⁺ sites, oriented along the cubic a-axis. Inelastic neutron scattering at 105 K reveals a strong peak at ∼276 meV and a weak transition at 366 meV. The former is consistent with the crystal field splitting of the Pr⁴⁺ J = frac(5, 2) ground state under the cubic point symmetry, while the latter peak is due to the intermultiplet transition between the J = frac(5, 2) ground state and J = frac(7, 2) excited state.