Itinerant antiferromagnetism in the Mott compoundV1.973O3

The doping-induced metallic state of the Mott system ${\mathrm{V}}_{2-y}{\mathrm{O}}_3$ has spin-density-wave order for $T<\mathrm{}{T}_N\approx 9$ K. Dynamic spin correlations in such a cation-deficient sample, ${\mathrm{V}}_{1.973}$ ${\mathrm{O}}_3$, were measured with inelastic neutron scattering throughout the Brillouin zone for energies up to $\sim 20k_B{T}_N$ and temperatures up to $\sim 20T_N$. The dynamic spin-correlation function, $S(\mathrm{q}, \omega )$, consists of a single ridge as a function of $\hslash \omega$ centered at each antiferromagnetic Bragg point. The q, $\omega$, and $T$ dependence of magnetic fluctuations can be described by the self-consistent renormalization theory for weak itinerant antiferromagnets developed by Moriya, Hasegawa, and Nakayama. Thermodynamic properties below $\sim 10T_N$ are quantitatively accounted for by this theory in its simplest form with only four parameters, which are determined by our neutron-scattering experiment.