The NSW interaction with nuclear local modes in antiferromagnets

The nuclear spin wave (NSW) relaxation rates due to the interaction with nuclear impurity local modes (NILM) in antiferromagnets are considered in the framework of the Keldysh formalism based on the spin operator diagram technique. It is shown that the NSW relaxation frequency due to the scattering on the fluctuations of impurity nuclear spins is of resonance character. The NSW damping due to the resonance absorption by NILM depends strongly on the NSW amplitude N, which accounts for the “hard” excitation of NSW's in parallel pumping experiments /6/. The NSW relaxation rates due to the processes involving two NSW's and one impurity nuclear excitation are also calculated.