Critical Nuclear Magnetic Relaxation in a Strong Itinerant-Electron Ferromagnet: Ni

Nuclear magnetic resonance has been observed in ferromagnetic Ni near the critical temperature. The nuclear spin-spin and spin-lattice relaxation rates are found to become equal in the critical region below $T_C$ and diverge with a critical exponent $n^{\prime }=0.67\mathrm{}\pm 0.08$. Spin-lattice relaxation rates in the paramagnetic state exhibit only incipient spin-fluctuation enhancement within the experimental range. Measurements of the ferromagnetic NMR frequency near $T_C$ and of the Knight shift above $T_C$ are described.