Generation of longitudinal acoustic waves by an excited acoustic subsystem during the movement of a domain wall in Yttrium orthoferrite

The purpose of this study is to determine the direct contribution of magnetic wave oscillations of magnetization during domain wall motion to the generation of longitudinal acoustic waves and their feedback effect on magnetization reversal processes in yttrium orthoferrite. Methods. The object of this study is the solution of a system of dynamic equations describing the interaction of magnetic and acoustic subsystems excited by a moving domain wall in yttrium orthoferrite. The equations are solved using perturbation theory, slowly varying amplitude theory, and Lagrangian methods. Results. For the first time, an explicit solution was obtained for the displacement of a longitudinal acoustic wave generated by a magnetic subsystem accompanying a moving domain wall in yttrium orthoferrite, taking into account the feedback effect of the acoustic wave. Using known values of the parameters included in the system of dynamic equations describing the interactions between the longitudinal acoustic wave and the magnetic subsystem during domain wall motion in yttrium orthoferrite, numerical calculations were performed based on the obtained solution. It is shown that the maximum contribution to a moving domain wall in yttrium orthoferrite due to the feedback effect of a longitudinal acoustic wave reaches about 10-12 m far from the wave velocity and increases by a factor of 104 (to about 10-8 m) at a domain wall velocity close to the wave velocity, i.e., it becomes comparable to its theoretical Landau thickness of ≈ 10-8 m. Conclusion. An explicit solution is obtained that takes into account the mutual influence of quasiparticle excitations accompanying transonic domain wall motion in yttrium orthoferrite on the interaction mechanisms of the magnetic and acoustic subsystems. This solution allows for meeting modern requirements for memory and logic devices in terms of quality and speed of information processing. Practically significant estimates of the contributions of such interactions are obtained for improving the component base of such devices.