AgCuVO4: A quasi one-dimensional S=1/2 compound

Recently, we have been able to synthesize the new copper-orthovanadate AgCuVO4. The crystal structure was determined by single crystal x-ray diffraction. AgCuVO4 comprises Cu2+ ions coordinated by oxygen in a square-planar fashion, similar to LiCuVO4, which has been identified as a multiferroic material recently. Whereas in LiCuVO4 the square-planar [CuO4] units are connected via edges to form chains along the crystallographic b axis, the [CuO4] units in AgCuVO4 are connected via corners resulting in Cu-O-Cu chains along the b-axis. The static magnetic susceptibility of AgCuVO4 can be described quite well within a Bonner-Fisher spin-chain scenario. In order to gain microscopic insight into the the electronic structure and the magnetic exchange interactions of AgCuVO4, we performed LDA band structure calculations. To take the strong Coulomb repulsion at the Cu site into account, we mapped the LDA results onto a tight binding model and subsequently onto a Heisenberg model. In agreement with the experimental data, we find pronounced one-dimensional magnetic exchange along the b axis with small inter-chain couplings.