Nuclear spin excitations in Nd

We have investigated the low-energy excitations in Nd in the μeV range by a back-scattering neutron spectrometer. The energy scans on Nd revealed inelastic peaks at E = 2.67 ′ 0.06 μeV at T = 60 mK on both energy-gain andenergy-loss sides. The inelastic peaks move gradually towards lower energy with increasing temperature, and finally merge with the elastic peak at zero energy transfer at the electronic magnetic ordering temperature T N 19.8 K. At about 5 K we observe a second peak at E = 1.8′0.3 μeV, which also decreases in energy with increasing temperature. This second peak disappears at about 15 K. We interpret the inelastic peaks as low-energy nuclear spin excitations arising due to the Suhl-Nakamura indirect interaction.