Ground State of the Quasi-1D \bvs\ resolved by Resonant Magnetic X-ray   Scattering
  Resonant-magnetic x-ray scattering (RMXS) near the vanadium $L_{2,3}$-absorption edges has been used to investigate the low temperature magnetic structure of high quality \bvs\ single crystals. Below $T_N$ = 31 K, the strong resonance revealed a triple-incommensurate magnetic ordering at wave vector (0.226 0.226 $\xi$) in the hexagonal notation, with $\xi$ = 0.033. The simulations of the experimental RMXS spectra with a time-dependent density functional theory indicate an antiferromagnetic order with the spins polarized along $a$ in the monoclinic structure. 
Ph. Leininger, V. Ilakovac, Y. Joly, E. Schierle, E. Weschke, O.   Bunau, H. Berger, J.-P. Pouget, P. Foury-Leylekian
cond-mat.str-el