Low-Temperature Magnetic Fluctuations Investigated by ¹²⁵Te-NMR on the Uranium-Based Superconductor UTe₂

To investigate the static and dynamic magnetic properties on uranium-based superconductor UTe$_{2}$, we measured NMR Knight shift $K$ nuclear spin-lattice relaxation rate $1/T_{1}$ in $H \parallel a$ by $^{125}$Te-NMR a $^{125}$Te-enriched single-crystal sample. $1/T_1T$ is much smaller than b$ $c$, fluctuations along each axis are derived from $H$ parallel to all three crystalline axes. The almost identical at two Te sites isotropic high temperatures, but become anisotropic below 40 K, where heavy-fermion state formed. character of UTe$_2$ discussed with comparison its susceptibility results other U-based superconductors. It considered that probed measurements determined inside two-leg ladder formed U atoms, which dominated $q_a$ = 0 ferromagnetic fluctuations.