Yevstafyev O. Explosive instability of magnetoelastic waves

Supercritical dynamics of nonlinear parametric instabilities is studied in two easy plane antiferromagnets (AFEP): hematite ?-Fe2O3 and iron borate FeBO3. These materials possess giant effective acoustic nonlinearity due to high magneto-elastic coupling. Limiting mechanisms of explosive dynamics were analyzed with the help of anharmonic approximation. Nonlinear frequency shift compensation via singular pumping field phase modulation was suggested and theoretically approbated. This technique was used for experimental investigation of supercritical explosive dynamics of three quasi-phonon excitations in magnetoelastic resonators. Iron borate studies were performed in the temperature range 77K - 293K where magnetoelastic parameters of the crystal vary essentially. Strongly nonlinear model of three quasi-phonon excitations in AFEPs was developed and numerically simulated. Theoretical studies of three travelling magnetoelastic waves coupling are performed on the basis of suggested theoretical models that take into account cubic nonlinearity of real AFEP crystals. Pumping phase modulation proportionally to wave amplitude is suggested to achieve explosive dynamics and spatial localization of generated triads.