Nonlinear magnetoacoustic waves in rare-earth orthoferrites.

The dynamics of magnetoacoustic waves in a rare-earth orthoferrite YFeO3 crystal is experimentally investigated. The waves are excited by a high-power laser pulse. The analysis of results is carried out taking into account the nonlinear interaction of oscillation modes. It allows us to interpret the results as energy exchange between modes in the time scale, a phenomenon known in nonlinear optics. Based on the proposed model an estimation is obtained for effective nonlinear magnetoacoustic modules of fourth order for yttrium orthoferrite approximately 2.5x 10(17) -2.5x 10(19) J/ m(3) .