title: Structure and Properties of Ir-Containing Oxides with Large Spin-Orbit Coupling: Ba2In(2-x)Ir(x)O(5+δ).
abstract: In this work, the solid solution series Ba2In(2-x)Ir(x)O5+δ (x = 0-1.4, 2) was synthesized, and its structural, magnetic, and charge-transport properties were measured. With increasing Ir content, three transitions in the room-temperature structure were observed: orthorhombic to tetragonal to cubic to a monoclinic distortion of a hexagonal BaTiO3 structure. Neutron diffraction shows Ba2In(1.6)Ir(0.4)O5.4 to be cubic and Ba2InIrO6 to be monoclinic, the latter contrary to previously published X-ray diffraction refinements. Magnetization measurements show Curie-Weiss behavior for x = 0.2-0.6, which arises from nearly 50:50 ratio of Ir(V) and Ir(VI). To our knowledge, this is the first time Ir(VI) has been stabilized with standard solid-state methods under ambient conditions. The electrical resistivity measurements show all the compounds studied are semiconducting and that resistivity decreases with increasing Ir content, suggesting the proximity to a metal-insulator transition. A sign reversal in the high-temperature Seebeck coefficient is observed indicating both electron and hole charge transport.
authors.affiliation: Department of Chemistry, Oregon State University , Corvallis, Oregon 97331, United States.
authors.forename: Joshua
authors.initials: J
authors.lastname: Flynn
authors.affiliation: Department of Chemistry, Oregon State University , Corvallis, Oregon 97331, United States.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Chemistry, Oregon State University , Corvallis, Oregon 97331, United States.
authors.forename: Arthur W
authors.initials: AW
authors.lastname: Sleight
authors.affiliation: Department of Physics, UC Santa Cruz , Santa Cruz, California 95064, United States.
authors.forename: Arthur P
authors.initials: AP
authors.lastname: Ramirez
authors.affiliation: Department of Chemistry, Oregon State University , Corvallis, Oregon 97331, United States.
authors.forename: M A
authors.initials: MA
authors.lastname: Subramanian