NMR, magnetization, and heat capacity studies of the uniform spin-1/2 chain compound Bi6V3O16

TL;DR

This study investigates the magnetic, NMR, and heat capacity properties of the spin-1/2 chain compound Bi6V3O16, revealing low-dimensional magnetism and site-specific valence states consistent with a uniform spin chain model.

Contribution

It provides detailed experimental characterization of Bi6V3O16, confirming its uniform spin-1/2 chain behavior and clarifying the valence state distribution of vanadium ions.

Findings

Magnetic susceptibility peaks around 50 K indicating short-range order.

NMR shows distinct V4+ and V5+ sites with no mixed occupation.

Spin susceptibility aligns with the S=1/2 uniform chain model with J=113 K.

Abstract

We report the local (NMR) and bulk (magnetization and heat capacity) properties of the vanadium-based S=1/2 uniform spin chain compound Bi6V3O16(Bi4V2O10.66). In the low-temperature {\alpha} 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 51V 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 51V NMR spectra reproduces the behavior observed in magnetic susceptibility and agrees well with the S=1/2 uniform spin chain model with J=113(5) K.