Mechanisms of Lamb Wave Generation by Domain Wall in a Plate of Weak Ferromagnetic

Abstract

The purpose of research. Study of the mechanism of Rayleigh-Lamb waves generation by the moving domain wall. Methods. The equations describing the elastic displacements generated by moving domain wall in the plate were solved by the Fourier method.

Results. For yttrium orthoferrite crystal we’ve estimated the amplitudes of Lamb waves displacement for two different cases of their generation: due to bulk and surface strains arising from the movement of the domain wall. The amplitude of displacement in an unbounded crystal has the same order of magnitude as for waves excited by surface strains - 10^-10 cm for the theoretical domain boundary thickness D₃ = 1.1·10^-6 m. The correlation between the contributions of bulk and surface mechanisms in the generation of Lamb waves by the domain wall has been determined.  

Conclusion. For development domain wall-based logic and memory devices it is necessary to fully investigate the factors that can affect the domain dynamics in magnetics. One of these factors is the braking of the domain wall on Rayleigh-Lamb waves. From the equations describing the elastic displacements in the orthoferrite crystal plate during the motion of the domain wall, we can conclude that there are two independent mechanisms of Rayleigh-Lamb waves generation - bulk and surface. The evaluation of the contributions of these mechanisms helps to consider the effect of surfaces on the domain dynamics and can be used in the future to develop magnetic memory devices based on weak ferromagnets.