We report, as an example, a complete analysis of nuclear spin-lattice relaxation time $\left(T_1\right)$ data for the strongly correlated antiferromagnet ${\mathrm{UPtGa}}_5$, which has a typical ${\mathrm{HoCoGa}}_5$ (115) structure. Using a high-quality single-crystal sample, the $T$ dependence of $T_1$ at ${}^{195}\mathrm{Pt}$ and at two crystallographically inequivalent ${}^{69}\mathrm{Ga}$ sites has been measured for $H\parallel a$ and $c$ axes. Using previously obtained hyperfine coupling tensors from static Knight shift results, the anisotropic spin fluctuation energy and $\vec{q}$ dependence of the dynamic susceptibility have been determined completely, forming a clear contrast to the cases of superconducting ${\mathrm{CeRhIn}}_5,{\mathrm{CeCoIn}}_5$, and ${\mathrm{CeIrIn}}_5$, which are considered to be very near to a quantum critical point. We also note that a similar hyperfine coupling scheme to that of ${\mathrm{CeRhIn}}_5$ has been found for ${\mathrm{UPtGa}}_5$.

• Received 23 March 2016
• Revised 1 May 2016

DOI:https://doi.org/10.1103/PhysRevB.93.205155