Magnetically pure spinel compound $\mathrm{Li}{\mathrm{V}}_2{\mathrm{O}}_4$ is a rare $d$-electron heavy fermion. Measurements on single crystals are needed to clarify the mechanism for the heavy-fermion behavior in the pure material. In addition, it is known that small concentrations $(<1\mathrm{mol}\%)$ of magnetic defects in the structure strongly affect the properties, and measurements on single crystals containing magnetic defects would help to understand the latter behaviors. Herein, we report flux growth of $\mathrm{Li}{\mathrm{V}}_2{\mathrm{O}}_4$ and preliminary measurements to help resolve these questions. The magnetic susceptibility of some as-grown crystals show a Curie-like upturn at low temperatures, showing the presence of magnetic defects within the spinel structure. The magnetic defects could be removed in some of the crystals by annealing them at $700°\mathrm{C}$. A very high specific heat coefficient $\gamma =450\mathrm{mJ}∕\mathrm{mol}{\mathrm{K}}^2$ was obtained at a temperature of $1.8\mathrm{K}$ for a crystal containing a magnetic defect concentration $n_{\text{defect}}=0.5\mathrm{mol}\%$. A crystal with $n_{\text{defect}}=0.01\mathrm{mol}\%$ showed a residual resistivity ratio of 50.

• Received 2 May 2007

DOI:https://doi.org/10.1103/PhysRevB.76.054418