Effect of Low-Temperature Structural Transformation onV51Knight Shifts and Electric Field Gradients inV3Si

Abstract

The nuclear magnetic resonance of ${\mathrm{V}}^{51}$ in ${\mathrm{V}}_3$Si has been observed in the presence of the low-temperature ${\mathrm{V}}_3$Si structural transformation. Both the nuclear-electric-quadrupolar interactions and the Knight shift of the field for resonance are affected by the transformation, with two distinguishable vanadium sites evolving. The nuclear resonance resolves values of $e^{2}qQ=2.674\mathrm{} \mathrm{MHz}\mathrm{and} 3.262 \mathrm{MHz}$ and Knight shift 0.41% and 0.45% for field perpendicular to the vanadium symmetry axis for the two sites, respectively. The changes result from changes in the electronic structure, the observed field-gradient change being some sixty times greater than the relative change in the point-charge contribution to the field gradient. The measurements were made in polycrystalline material, and present a means of detecting structural transformations in polycrystalline metals. The effects of possible further distortions within the unit cell are considered.