We have shown that, in the presence of a strong ac magnetic field, the parametric interaction of two weak acoustic waves occurs in a crystal of molecular magnets. Any magnetic molecule is subject to a dc magnetic field perpendicular to its easy anisotropy axis. The ac magnetic field is parallel to this axis. The frequencies of the ac magnetic field and acoustic waves are close to the transition frequency of the fundamental doublet. The acoustic waves propagate in opposite directions. We have derived equations for the amplitudes of the two coupled acoustic waves. Due to the parametric interaction, one acoustic wave input into the sample excites the second acoustic wave.

• Received 8 December 2004

DOI:https://doi.org/10.1103/PhysRevB.71.094431