The effect of dissipation and an external magnetic field on the resonance dynamics of a domain wall in a five-layer ferromagnetic structure

摘要

By the example of a five-layer ferromagnetic structure with two thin and three wide magnetic layers, the influence of attenuation and an external constant magnetic field on the dynamics of the domain wall (DW) is considered. It is shown that the features of the dynamics of the domain wall in a multilayer magnetic system in the presence of thin magnetic layers with a reduced value of the magnetic anisotropy constant are largely related to the resonant energy exchange between magnetic inhomogeneities. A diagram of the possible scenarios of the dynamics of the domain wall is constructed depending on the initial velocity of its movement and the distance between two identical thin magnetic layers. The presence of a critical distance was found that separates the dynamics of the domain wall into two regions with qualitatively different system behavior. In the first region, where the distance between the thin layers is rather small, the scattering of the domain wall occurs similarly to the case of the three-layer system studied earlier. In the second region, a much more complex dynamics of the scattering of the domain wall is observed, associated with the interaction of the domain wall and a localized nonlinear magnetization wave. The main effects of the collective influence of thin layers on the dynamics of the DW are preserved under the action of an external force, whereas when the DW moves by inertia, it almost completely disappears. A new dynamic effect of “quasitunneling” of the domain boundary, i.?e. the passage of the domain boundary through the effective potential barrier, which appears due to the presence of two thin layers in the system at speeds lower than the minimum value for the case of a single thin layer. The result obtained - the existence of a range of parameters in which substantially less energy is required for a domain wall to pass through both thin layers can be interesting from a practical point of view.