${}^{235}\text{U}$ nuclear spin-lattice $\left(T_1^{-1}\right)$ and spin-spin $\left(T_2^{-1}\right)$ relaxation rates in the itinerant antiferromagnet ${\text{USb}}_2$ are reported as a function of temperature in zero field. The heating effect from the intense rf pulses that are necessary for the ${}^{235}\text{U}$ NMR results in unusual complex thermal recovery of the nuclear magnetization which does not allow measuring $T_1^{-1}$ directly. By implementing an indirect method, however, we successfully extracted $T_1^{-1}$ of the ${}^{235}\text{U}$. We find that the temperature dependence of $T_1^{-1}$ for both ${}^{235}\text{U}$ and ${}^{121}\text{S}\text{b}$ follows the power law $\left(\propto T^n\right)$ with the small exponent $n=0.3$ suggesting that the same relaxation mechanism dominates the on-site and the ligand nuclei, but an anomaly at 5 K was observed, possibly due to the change in the transferred hyperfine coupling on the Sb site.

• Received 9 November 2009

DOI:https://doi.org/10.1103/PhysRevB.81.054435