THE MAGNETIC-PROPERTIES OF IRIDIUM IN MIXED-METAL OXIDES

The magnetic susceptibilities of La2Mg1-xZnIrO6 (0 <x < 1), La2NiIrO6, La2CuIrO6, La2LiIrO6, BaLaMgIrO6, BaLaFeIrO6, BaLaCoIrO6, BaLaNiIrO6 and Sr4IrO6 have been measured as a function of temperature and applied magnetic field. Sr4IrO6, BaLaNiIrO6 and BaLaCoIrO6 order antiferromagnetically at 12, 87 and 56 K respectively. BaLaFeIrO6 shows a spin-glass transition at 65 K. La2NiIrO6 and La2CuIrO6 order as weak ferromagnets at 80 K and 70 K respectively. The solid solution La2Mg1-xZnxIrO6 shows a gradual change from antiferromagnetism (TN = 11.7 K) when x = 0 to ferromagnetism (T(c) = 9.5 K, mu(sat) = 0.4 mu(B)) when x = 1. The Ir(V) oxides La2LiIrO6 and BaLaMgIrO6 are paramagnetic in the temperature range 6 K<T<300 K.