Phase relations in the Li2O-V2O3-V2O5 system at 700 °C : Correlations with magnetic-defect concentration in heavy fermion LiV2O4

The phase relations in the ${\mathrm{Li}}_{2}\mathrm{O}\text{\ensuremath{-}}{\mathrm{V}}_{2}{\mathrm{O}}_{3}\text{\ensuremath{-}}{\mathrm{V}}_{2}{\mathrm{O}}_{5}$ ternary system at $700\phantom{\rule{0.2em}{0ex}}\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ for compositions in equilibrium with $\mathrm{Li}{\mathrm{V}}_{2}{\mathrm{O}}_{4}$ are reported. This study clarified the synthesis conditions under which low and high magnetic defect concentrations can be obtained within the spinel structure of $\mathrm{Li}{\mathrm{V}}_{2}{\mathrm{O}}_{4}$. We confirmed that the $\mathrm{Li}{\mathrm{V}}_{2}{\mathrm{O}}_{4}$ phase can be obtained containing low $(0.006\phantom{\rule{0.3em}{0ex}}\mathrm{mol}\phantom{\rule{0.2em}{0ex}}%)$ to high $(0.83\phantom{\rule{0.3em}{0ex}}\mathrm{mol}\phantom{\rule{0.2em}{0ex}}%)$ magnetic defect concentrations ${n}_{\text{defect}}$ and with consistently high magnetic defect spin $S$ values between 3 and 6.5. The high ${n}_{\text{defect}}$ values were obtained in the $\mathrm{Li}{\mathrm{V}}_{2}{\mathrm{O}}_{4}$ phase in equilibrium with ${\mathrm{V}}_{2}{\mathrm{O}}_{3}$, ${\mathrm{Li}}_{3}\mathrm{V}{\mathrm{O}}_{4}$, or $\mathrm{Li}\mathrm{V}{\mathrm{O}}_{2}$ and the low values in the $\mathrm{Li}{\mathrm{V}}_{2}{\mathrm{O}}_{4}$ phase in equilibrium with ${\mathrm{V}}_{3}{\mathrm{O}}_{5}$. A model is suggested to explain this correlation.