Decay kinetics of metastable spin-aligned crystals

The decay kinetics of metastable spin-aligned atomic crystals is considered. It is shown that the most rapid decay channels due to the creation of spin waves may be suppressed by means of the external magnetic field applied against the direction of magnetic momenta polarization. The primary channels of decay which cannot be eliminated by magnetic field are connected with the decay of the polarized state into one magnon and two phonons due to dipole-dipole interaction and into one magnon and one phonon due to a second order process that is associated simultaneously with the hyperfine interaction and the magnon-phonon interaction.