Lithium ruthenates. Controlling dimensionality and topology of magnetic-ion arrangements

In order to control the dimensionality and the topology of the arrangement of magnetic Ru ions, NaCl-type lithium ruthenates have been investigated. Three types of lithium ruthenates, Li3RuO4, Li2RuO3, and cubic-LixRuO1+x, were synthesized using a hydrothermal method. All of them have NaCl-type structure, but the arrangements of the cations, Li+ and Ru5+ (or Ru4+), differ from each other. Li3RuO4 with one-dimensional zigzag chains of Ru ions undergoes an antiferromagnetic transition at 66 K and exhibits an irreversible magnetism below 32 K, where the zero-field-cooled susceptibility differs from the field-cooled susceptibility. Li2RuO3 with a two-dimensional honeycomb network of Ru ions demonstrates a paramagnetism almost independent of temperature. A novel ruthenate cubic-LixRuO1+x, in which Ru and Li randomly occupy the cation sites of NaCl lattice, undergoes a spin-glass transition at 10 K. (author)