The Kondo lattice compound ${\mathrm{YbV}}_6{\mathrm{Sn}}_6$ has recently been discovered to exhibit antiferromagnetic order at $T_{\mathrm{N}}\approx 0.4\mathrm{K}$ and features a layered structure that combines a triangular lattice network of ${\mathrm{Yb}}^{3+}$ ions with a vanadium-based kagome network. We report a ${}^{51}\mathrm{V}$ nuclear magnetic resonance (NMR) study of the paramagnetic state of ${\mathrm{YbV}}_6{\mathrm{Sn}}_6$. Detailed field-angular dependence of single-crystal NMR spectra determined the principal-axis directions of the electric field gradient tensor at the ${}^{51}\mathrm{V}$ sites, as well as their nuclear quadrupole frequency, ${\nu }_{\mathrm{Q}}$, and asymmetry parameter, $\eta$. The Knight shift, $K$, was measured for different field orientations, and the analysis of $K$ against magnetic susceptibility was used to extract anisotropic hyperfine couplings. Accurate spectral assignments further enabled measurements of the nuclear spin-lattice relaxation rate, $1/T_1$, for both in-plane and out-of-plane field directions. Below $\sim 20\mathrm{K}$, comparable to the energy separation between the crystalline electric field ground-state and first excited doublets of ${\mathrm{Yb}}^{3+}, 1/T_1$ reveals enhanced low-energy spin fluctuations with pronounced in-plane anisotropy. Upon further cooling below $\sim 10\mathrm{K}$, a strongly field-tunable enhancement emerges, suggesting proximity to the very-low-temperature antiferromagnetic instability.

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• Magnetic anisotropy
• Magnetism
• Spin dynamics
• Kagome lattice
• Single crystal materials
• Triangular lattice
• Kondo lattice model
• Nuclear magnetic resonance
• Nuclear magnetic resonance relaxation rate