V-V Dimerization and Magnetic State of Cobalt Ions in Ilmenite-Type CoVO.

The nature of chemical bonds determines the electronic and magnetic properties of compounds. A metal-metal bonding (V-V dimer) and its effect on the magnetism of ilmenite-type CoVO were studied. Polycrystalline CoVO samples were synthesized using a high-pressure synthesis method. Crystal structure refinement revealed that V-V dimers exist at temperatures below 550 K in the vanadium layers. Co in CoVO exhibits an = 3/2 state, whereas a = 1/2 state was reported in ilmenite-type CoTiO. The existence of V-V dimers reduces the structural symmetry (from 3 to 1), which can change the magnetic ground state.