NMR and bulk studies on S=1/2 spin chain Bi₆V₃O₁₆

We report the NMR and bulk properties of a vanadium based S=1/2 spin chain compound Bi₆V₃O₁₆ in its low temperature phase where the magnetic V⁴⁺ ions are arranged in a one-dimensional chain mediated by V⁵⁺ and oxygen ions. We have carried out magnetic and heat capacity measurements, both static and magic angle spinning (MAS) ⁵¹V NMR measurements and analysis for unaligned powder sample. The magnetic susceptibility χ shows a broad maximum around 50 K signifying a short-range magnetic order which matches well with the S=1/2 Heisenberg chain model. In the NMR measurements, we only detected the non-magnetic ⁵¹V. The spin susceptibility calculated from the shift of the static ⁵¹V NMR spectra reproduces well the behavior observed in χ. The MAS NMR experiments reproduce the trend observed in χ and static NMR with unprecedented accuracy, and confirm that there is only one site the V⁴⁺ ions are occupying. We have also performed and analyzed spin-lattice relaxation measurements of ⁵¹V.