Structural and electronic properties of the compounds Ba4Ir3MO12(M = Li, Na, Mg, Y, Lu, Zr and Ce)

Abstract

Polycrystalline samples of the Ir^IV/Ir^V compounds Ba₄Ir₃MO₁₂(M = Li, Na, Mg, Y, Lu, Zr and Ce) have been prepared using standard ceramic techniques. The products have been characterized by X-ray powder diffraction, SQUID magnetometry (6<T/K <296) and electrical conductivity measurements 80<T/K <296). They all adopt the 6H perovskite structure with the cation M occupying only the vertex-sharing six-coordinate sites and with iridium occupying the face-sharing sites and the remaining 25% of the vertex-sharing sites. These compounds are non-metallic and have low magnetic susceptibilities with only a relatively small temperature dependence, suggesting that extensive spin-pairing occurs throughout the measured temperature range.