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arXiv · 0911.3068

$^{235}$U nuclear relaxation rates in an itinerant antiferromagnet USb$_2$

S. -H. Baek·N. J. Curro·H. Sakai·E. D. Bauer·J. C. Cooley·J. L. Smith
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Abstract

$^{235}$U nuclear spin-lattice ($T_1^{-1}$) and spin-spin ($T_2^{-1}$) relaxation rates in the itinerant antiferromagnet 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 $^{235}$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 $^{235}$U. We find that the temperature dependence of $T_1^{-1}$ for both $^{235}$U and $^{121}$Sb follows the power law ($\propto T^n$) 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.

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S. -H. Baek, N. J. Curro, H. Sakai, E. D. Bauer, J. C. Cooley, J. L. Smith. 2010-02-24. $^{235}$U nuclear relaxation rates in an itinerant antiferromagnet USb$_2$. https://doi.org/10.1103/physrevb.81.054435

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