Abstract

The crystal structures and magnetic properties of ordered perovskites Ba₂LnIrO₆ (Ln = lanthanide) are reported. They were determined to have monoclinic perovskite-type structures with space group P2₁/n. Their magnetic susceptibilities were measured from 2 to 350 K. Ba₂CeIrO₆ and Ba₂PrIrO₆ show antiferromagnetic transitions at 17 and 71 K, respectively. In these compounds, the Ce and Pr ions are found to be in the tetravalent state from analysis of their crystal structures and magnetic susceptibilities.