We investigated the dispersion of nuclear spin waves in Nd$_2$CuO$_4$ by using neutron spin-echo spectroscopy at millikelvin temperatures. Our results show unambiguously the existence of dispersion of nuclear spin waves in Nd$_2$CuO$_4$ at T = 30 mK.
A fit of the dispersion data with the spin wave dispersion formula gave the Suhl-Nakamura interaction range to be of the order of 10 {AA}.
