The effect of iridium oxidation state on the electronic properties of perovskite-type solid solutions: Ba2–La InIrO6 and BaLaIn1–Ca IrO6

Abstract

Two novel solid solution series, Ba 2-x La x InIrO 6 (x = 0-1.0) and BaLaIn 1-y Ca y IrO 6 (y = 0-1.0), were prepared and several changes in structure, moment and charge transport were observed. The Ba 2x La x InIrO 6 series exhibits a transition from a 6M polytype to an orthorhombic perovskite structure with increased La content whereas the BaLaIn 1-y Ca y IrO 6 series transitioned from a disordered, orthorhombic perovskite to an ordered, cubic perovskite with increased Ca content. Seebeck measurements for both systems showed that Ir(IV)-rich compounds tended to have a n-type conduction mechanism while Ir(V)rich compounds tended to be p-type. Both systems were found to be semiconducting and the magnitude of the resistivity is dependent on crystal structure and Ir environment. Magnetic measurements show that the values for both systems are significantly less than predicted for Ir(IV) (1.73) and greater than predicted for Ir(V) (0). These results are compared to other iridate compound families.

Probing the tunability of magnetism with external pressure in metastable Sr2NiIrO6 double perovskite

“…In relation to the value of the local (atomic) magnetic moment of Ir, it should be noted that, to the best of our knowledge, neither FM nor ferrimagnetic (FiM) structure has been reported yet for any Ir oxide. For AFM systems (typically canted AFM), disparate values have been reported for the Ir magnetic moment [16][17][18][19][20][21][22][23], likely associated with the difficult detection of Ir magnetic moment by the typically used neutron powder diffraction technique. In this work we propose a combined HP-XRD, HP-EXAFS, and HP-XMCD study of Sr 2 NiIrO 6 oxide to get further insight into these questions.…”