Spin-Orbit Coupling Controlled Ground State in the Ir(V) Perovskites AScIrO (A = Ba or Sr).

The structural and magnetic properties of the two Ir(V) perovskites BaScIrO and SrScIrO were established. The structures were refined using a combined neutron and synchrotron data set. At room temperature the former has a cubic structure in space group Fm3̅m with a = 8.1450(3) Å, and the latter is monoclinic in P2/n with a = 5.6606(3) Å, b = 5.6366(3) Å, c = 7.9720(4) Å, and β = 89.977(5)°. Magnetization measurements show both oxides have magnetic moments close to zero as a consequence of strong spin-orbit coupling that results in a J ≈ 0 ground state. The distortion of the IrO octahedra in SrScIrO is insufficient to generate crystal field splitting strong enough to quench the spin-orbit coupling.