Dynamical Behavior of Spins in the Rare-Earth Kagomé Pr${}_3$Ga${}_5$SiO${}_{14}$

Abstract

We report on the use of ${}^{69,71}$Ga nuclear magnetic resonance to probe spin dynamics in the rare-earth kagomé system Pr${}_3$Ga${}_5$SiO${}_{14}$. We find that the spin-lattice relaxation rate ${}^{69}1/T_1$ exhibits a maximum around 30 K, below which the Pr${}^{3+}$ spin correlation time $\tau$ shows novel field-dependent behavior consistent with a field-dependent gap in the excitation spectrum. The spin-spin relaxation rate ${}^{69}1/T_2$ exhibits a peak at a lower temperature (10 K) below which field-dependent power-law behavior close to $T^2$ is observed. These results point to field-induced formation of nanoscale magnetic clusters consistent with recent neutron scattering measurements.