Magnetic Properties Of The Doped Spin-1/2 Honeycomb-Lattice Compound In3cu2vo9

We report magnetic properties in the Co- and Zn-doped spin-1/2 honeycomb-lattice compound In3Cu2VO9. Magnetic susceptibility and specific heat experiments show no long-range ordering down to 2 K in In3Cu2VO9. Analyses of electronic structures and states suggest that the ground state of undoped In3Cu2VO9 is probably a Neel antiferromagnet (AFM). When Cu2+ ions are partially substituted by Co2+ ions, both the impurity potential scattering and magnetic scattering induced by the magnetic Co2+ ions enhance the three-dimensional character of the magnetic coupling and lead to an AFM long-range order. Replacement of Cu2+ with nonmagnetic Zn2+ ions weakens the AFM correlation between Cu2+ ions, leading to suppression of the AFM state.