We report on the destabilization of the 6H-SrIrO 3 polymorph through partial substitutions of zinc and lithium for iridium to form perovskites. The perovskites crystallize in the orthorhombic space group Pbnm: SrIr 1-xZn xO 3 is found for 0.25 ≤ x ≤ 0.33, while SrIr 1-xLi xO 3 is found only for x = 0.25. The Zn and Li ions are randomly distributed in the B-site lattice. Analysis shows that the perovskite stabilization is not driven by changes in average ionic size but rather is due to destabilization of the face-sharing octahedra that are present in 6H-type SrIrO 3. Magnetic susceptibility measurements show Curie-Weiss behavior, with relatively large temperature independent contributions, and that the iridium atoms have low effective moments, 0.52 to 1.08 μ B per Ir. The resistivity of SrIr 0.67Zn 0.33O 3, characterized by Mott variable range hopping type semiconducting behavior, indicates that substituted Zn ions introduce significant disorder into the system. SrIr 0.75Li 0.25O 3 has a significant linear contribution to the specific heat at low temperatures.
All Science Journal Classification (ASJC) codes
- Materials Chemistry