Chain segmentation and the origin of low-T magnetic moments in quasi one-dimensional Ba2V3O9

Experimentally observed upturns in the low-temperature magnetic susceptibility of one-dimensional spin (1/2) antiferromagnets like Ba2V3O9 are frequently attributed to a staggered-field mechanism due to the presence of a g-factor anisotropy or a sizeable Dzyaloshinskii-Moriya interaction. For Ba2V3O9, this mechanism is far too small to explain the experimental results. Instead, numerical investigations of small clusters using the finite-temperature Lanczos method suggest that the Curie upturn is due to a segmentation of spin chains caused by broken magnetic bonds between adjacent VO6-octahedra