Vesignieite BaCu3V2O8(OH)2 as a Candidate Spin-1/2 Kagome Antiferromagnet

A polycrystalline sample of vesignicite BaCu3V2O8(OH)(2) comprising a nearly ideal kagome lattice composed of Cu2+ ions carrying spin 1/2 has been synthesized and studied by magnetization and heat capacity measurements. Magnetic susceptibility shows a neither long range order, a spin glass transition nor a spin gap down to 2 K, in spite of a moderately strong antiferromagnetic interaction of J/k(B) = 53 K between nearest-neighbor spins. A broad peak observed at a temperature corresponding to 0.4J in intrinsic magnetic Susceptibility indicates a marked development of the short-range order. The ground state of vesignicite is probably a gapless spin liquid or is accompanied by a very small gap less than similar to J/30.