D ec 1 99 9 Spin - wave contributions to nuclear magnetic relaxation in magnetic metals

The longitudinal and transverse nuclear magnetic relaxation rates 1/T1(T ) and 1/T2(T ) are calculated for threeand two-dimensional (3D and 2D) metallic ferroand antiferromagnets (FM and AFM) with localized magnetic moments in the spin-wave temperature region. The contribution of the onemagnon decay processes is strongly enhanced in comparison with the standard T -linear Korringa term, especially for the FM case. For the 3D AFM case this contribution diverges logarithmically, the divergence being cut at the magnon gap ω0 due to magnetic anisotropy, and for the 2D AFM case as ω −1 0 . The electron-magnon scattering processes yield T 2 ln(T/ω0) and T 2/ω 1/2 0 -terms in 1/T1 for the 3D AFM and 2D FM cases, respectively. The two-magnon (“Raman”) contributions are investigated and demonstrated to be large in the 2D FM case. Peculiarities of the isotropic 2D limit (where the correlation length is very large) are analyzed. Typeset using REVTEX 1