Synthesis and magnetic properties of 12L-perovskites Ba4LnIr3O12 (Ln=lanthanides)

New quadruple perovskite oxides Ba4Ln Ir3O12 (Ln =lanthanides) were prepared and their magnetic properties were investigated. They crystallize in the monoclinic 12L-perovskite-type structure with space group C 2/m . The Ir3O12 trimers and LnO6 octahedra are alternately linked by corner-sharing and form the perovskite-type structure with 12 layers. The Ln and Ir ions are both in the tetravalent state for Ln =Ce, Pr, and Tb compounds View the MathML source(Ba4Ln4+Ir34+O12), and for other compounds (Ln =La, Nd, Sm–Gd, Dy–Lu), Ln ions are in the trivalent state and the mean oxidation state of Ir ions is View the MathML source+4.33(Ba4Ln3+Ir34+.33O12). An antiferromagnetic transition has been observed for Ln=Ce, Pr, and Tb compounds at 10.5, 35, and 16 K, respectively, while the other compounds are paramagnetic down to 1.8 K.