The phase relations in the ${\mathrm{Li}}_2\mathrm{O}\text{−}{\mathrm{V}}_2{\mathrm{O}}_3\text{−}{\mathrm{V}}_2{\mathrm{O}}_5$ ternary system at $700°\mathrm{C}$ 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 $(0.006\mathrm{mol}\%)$ to high $(0.83\mathrm{mol}\%)$ 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.

• Received 31 July 2006

DOI:https://doi.org/10.1103/PhysRevB.74.184417