Local Electric Properties of β-Ag_0.33V₂O₅Studied by⁵¹V NMR

Abstract

Local spin and charge properties were studied on β-Ag0.33V2O5, a pressure-induced superconductor, at ambient pressure using 51 V-NMR and zero-field-resonance (ZFR) techniques. Three inequivalent Vi sites (i=1, 2, and 3) were identified from 51 V-NMR spectra and the principal axes of the electric-field-gradient (EFG) tensor were determined in a metallic phase and the following charge-ordering phase. We found from the EFG analysis that the V1 sites are in a similar local environment to the V3 sites. This was also observed in ZFR spectra as pairs of signals closely located with each other. These results are well explained by a charge-sharing model where a 3d 1 electron is shared within a rung in both V1-V3 and V2-V2 two-leg ladders.

Applications of nuclear shielding

“…104 The local electric properties of b-Ag 0.33 V 2 O 5 were studied at ambient pressure by using 51 V NMR technique, and the principal axes of the EFG tensor, electric quadrupole frequency, asymmetric parameter and Knight shift for each Vi site in the metallic phase and the subsequent charge-ordering (CO) phase at low temps were determined. 105 The 51 V NMR study on the single crystal BaCo 2 V 2 O 8 at temperatures between 3 and 300 K was reported and no substantial changes in the NMR shift and line width at low temperatures were found as a constant field of 7.06 T was applied along the c-axis. 106 Chemical shifts and line widths of the three characteristic signals in the 51 V NMR spectrum of decavanadate, corresponding to vanadium atoms in equatorial peripheral, equatorial interior and axial locations were studied.…”