NMR, magnetization, and heat capacity studies of the uniform spin- 12 chain compound Bi6 V3 O16

Abstract

We report the local (NMR) and bulk (magnetization and heat capacity) properties of the vanadium-based S=12 uniform spin chain compound Bi6V3O16(Bi4V2O10.66). In the low-temperature α phase, the magnetic ions (V4+) are arranged in one-dimensional chains. The magnetic susceptibility shows a broad maximum around 50 K signifying a short-range magnetic order. Heat capacity measurements also reveal low-dimensional magnetism. The V51 magic angle spinning nuclear magnetic resonance measurements clearly show that the magnetic V4+ and nonmagnetic V5+ species are located on different crystallographic sites with no mixed occupation. The spin susceptibility calculated from the shift of the V51 NMR spectra reproduces the behavior observed in magnetic susceptibility and agrees well with the S=12 uniform spin chain model with J=113(5) K.