Magnetic susceptibility of Ba2YbTaO6 with the ordered perovskite structureand electron paramagnetic resonance of Yb3+ doped in Ba2LuTaO6

A quaternary oxide, Ba2YbTaO6, was prepared, and its powder X-ray diffracti on measurements and the Rietveld analysis show that it is cubic with the sp ace group Fm (3) over bar m and that Yb3+ and Ta5+ ions are structurally or dered. Magnetic susceptibilities of Ba2YbTaO6 were measured in the temperat ure range between 5 K and room temperature, and the electron paramagnetic r esonance (EPR) spectrum of Yb3+ ion doped in Ba2LuTaO6 was measured at 8 K. This compound is paramagnetic down to 5 K, and the temperature dependence of its susceptibility was analysed with the crystal field model. Hyperfine interaction was observed for the EPR spectrum of Yb3+/Ba2LuTaO6. Analysis o f the EPR data indicates the existence of the covalency in the Yb3+ ion in an octahedral symmetry. (C) 2000 Academic Press.