V–V Dimerization and Magnetic State of Cobalt Ions in Ilmenite-Type CoVO<sub>3</sub>
Sachiko Kamiyama, Ikuya Yamada, Masayuki Fukuda, Yuichi Okazaki, Takashi Nakamura, Takumi Nishikubo, Masaki Azuma, Hiroyuki Kimura, Hajime Yamamoto
Abstract
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 CoVO3 were studied. Polycrystalline CoVO3 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. Co2+ in CoVO3 exhibits an S = 3/2 state, whereas a Jeff = 1/2 state was reported in ilmenite-type CoTiO3. The existence of V–V dimers reduces the structural symmetry (from R3 to P1), which can change the magnetic ground state.