Direct evidence for nuclear spin waves in Nd2CuO4 by high-resolution neutron-spin-echo spectroscopy

The possibility of coupling through the hyperfine interaction of nuclear spins with the electronic spin system has given rise to hope for potential novel applications in spintronics and quantum computations. We investigated the dispersion of nuclear spin waves in such a coupled system, Nd2CuO4, by using neutron-spin-echo spectroscopy at millikelvin temperatures. Our results show the existence of dispersion of nuclear spin waves in Nd2CuO4 at T = 40 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 Å, which is much smaller than that expected theoretically. (paper)