On the sound absorption in ferrodielectrics

The damping of the sound waves in ferromagnets due to the phonon-magnon interaction is considered for the temperature $\text{θ}{}_{\mathrm{c}}\text{(}\text{μM}{}_0\text{4}\text{7θ}{}_{\mathrm{c}}\text{)}{}^{\mathrm{<mtext>4</mtext><mtext>7</mtext>}}\text{? T ?}\text{θ}{}^2{}_{\mathrm{D}}\text{4}\text{7θ}{}_{\mathrm{c}}$ and frequency τ^?1_m-ph ? ω ? τ^?1_m ranges. This damping is found to be greater than the Landau-Rumer one due to the anharmonic interactions in the crystal. The Akhiezer's method for the calculation of the sound damping is shown to be valid for the more wide frequency range than it was regarded earlier.