Site-Selective NMR in the Quasi-1D Conductor beta-Sr0.33V2O5

TL;DR

This study uses site-selective NMR to investigate the magnetic and charge properties of beta-Sr0.33V2O5, revealing heterogeneity among vanadium sites and evidence of ferromagnetic correlations at specific sites.

Contribution

First detailed site-specific NMR analysis of beta-Sr0.33V2O5 revealing charge disproportionation and magnetic heterogeneity.

Findings

Heterogeneous magnetic properties among vanadium sites.

Charge disproportionation observed in V2 ladder units.

Evidence of ferromagnetic correlations at specific sites.

Abstract

We report 51V NMR experiments in the metallic phase of the quasi-one-dimensional (1D) conductor beta-Sr0.33V2O5. The Knight shift and the quadrupole splitting of all six vanadium sites were determined as a function of the direction of magnetic field perpendicular to the conducting b-axis. Magnetic properties of the three 1D structural units are remarkably heterogeneous. In particular, the V2 ladder unit shows pronounced charge disproportionation among the two (V2a and V2b) sites. At one of these sites, the absolute value of the Knight shift and 1/(T1T) increase steeply with decreasing temperature, suggesting development of ferromagnetic correlation.