7 Li and 51 V NMR study of the heavy-fermion compound LiV 2 O 4

摘要: ${}^{7}\mathrm{Li}$ and ${}^{51}\mathrm{V}$ NMR Knight shift, linewidth, spin-lattice, spin-spin relaxation rate data are reported as a function of temperature $T$ (1.5--800 K 74--575 for Li V nuclei, respectively) in the heavy fermion compound ${\mathrm{LiV}}_{2}{\mathrm{O}}_{4}$. The shift $K$ exhibits broad maximum at about 25 is nearly constant below 4.2 K, linewidth. negative 575 it decreases strongly lowered. Above \ensuremath{\sim}80 both shifts proportional to susceptibility from slope hyperfine coupling can be obtained nuclei. spin-lattice increases lowered room reaching 50 K. Below 5 linearly with normal metals but very high value Korringa product ${(T}_{1}{T)}^{\ensuremath{-}1}$. Even so, ratio ${K}^{2}{T}_{1}{T/S}_{\mathrm{Li}}$ $\ensuremath{\sim}$ 10 on order unity conventional metals, thus indicating Fermi liquid behavior. From an analysis we infer approximate square root dependence local moment spin-relaxation temperatures $(T\ensuremath{\gtrsim}50$ K). A simplified yields 17 meV magnitude exchange between moments conduction electrons 2.3 that neighboring moments. Quantitative discrepancies rates low what expected uniform indicate effects such Kondo effect screening and/or dynamical vanadium ${t}_{2g}$ orbital occupation correlation/fluctuation may present our system.