NMR measurement of spin-spin relaxation (T$_{2})$ of URu$_{2}$Si$_{2}$

We report detailed temperature dependences of the 29Si spin-spin relaxation rate T2 in the heavy fermion superconductor URu$_{2}$Si$_{2}$ as a function of field and temperature.~ All experimental work was carried out on an aligned powder sample.~ Both Carr-Purcell-Meiboom-Gill (CPMG) and Hahn-Echo pulse sequence techniques were employed to examine differences in spin-spin relaxation.~ We find unusual enhancements of the relaxation rate near the hidden order transition, and will discuss our results in the context of various theoretical scenarios.