Magnetic Order in the Spin-1/2 Kagome Antiferromagnet Vesignieite

We report results of magnetic susceptibility and 51V- and 63,65Cu-NMR measurements on a high-quality powder sample of vesignieite BaCu3V2O8(OH)2, a candidate for the spin-1/2 kagome antiferromagnet. We observed a two-step magnetic transition: the appearance of spatially inhomogeneous static moments below 13 K and a long-range order below 9 K. The NMR data indicate a \(\mathbf{Q}= 0\) magnetic structure at 1.4 K with the in-plane spin components of three sublattices oriented at nearly 120\circ to each other and the magnitude of the ordered moments of at least 0.6 μB.