Nuclear magnetic relaxation in the domain and domain wall of pure iron

The nuclear magnetic relaxation times in the domain and domain wall of pure natural iron have been measured separately. We have witnessed that the spin-spin relaxation time T-2 is longer than the spin-lattice relaxation time T-1 in the domain wall. The ratio T-2/T-1 increases and approaches 2 with decreasing rf pulse power level. This is due to the anisotropy in the fluctuation of the hyperfine field by single magnon processes or wall-type excitations. The measured spin-spin relaxation rate is well described by the sum of the nonsecular term and the dipole-dipole interaction term.