Crystal growth and magnetic properties of the new iridates Ln1?xNa1+xIrO4 (Ln = Gd–Er,Y; x = 0.04–0.25)

We report the single crystal structures and magnetic properties of a series of lanthanide-containing iridates, Ln_1?xNa_1+xIrO₄ (Ln = Gd–Er, Y; x = 0.04–0.26) grown from a mixed sodium and cesium hydroxide flux. The compounds crystallize in the hexagonal space group P-62m (#189) with lattice parameters ranging from a = 9.3872(2)–9.4596(3) Å and c = 3.1512(1)–3.2030(2) Å and are structurally related to other iridium oxides. The oxidation state of iridium ranges from +4.08 (Gd) to +4.50 (Er). Magnetic susceptibility measurements reveal the existence of antiferromagnetic correlations below 15 K.