Studying the nucleation and evolution of magnetic inhomogeneities of the soliton and breather type in magnetic materials with local inhomogeneities of anisotropy

Numerical simulation of the generation of multisoliton type magnetic inhomogeneities in ferromagnets with inhomogeneous parameters

“…The characteristic frequencies amount to ω trans =0.429, ω pulse =0.875, ω breather =0.92 (Fig.2). If we compare the values of the excited pulsation and transmission kink modes and oscillation breather frequencies for a single impurity [11], we shall see that they practically coincide. Thus, the soliton interaction in the impurity area is not observed at high d parameters.…”

“…Common numerical realizations of the Eq. (1) used in [11,15] enable us to calculate the kink structure and dynamics accurately enough to watch the kink pinning and passing through the impurities, structure and properties of the non-linear waves excited. Yet much higher accuracy is required to study possible resonance effects.…”

“…By considering that the energy density of the magnet takes into account the exchange interaction and anisotropy, the equation of motion for the magnetization in the angular variables m = m (0, sinθ, cosθ) can be represented in the dimensionless form [11] ( )…”

“…It should be noted that, in a defect-free magnet, magnetic inhomogeneities of 0° domain wall type are energetically unfavorable as compared to the homogeneous state of the magnetization vector. The presence of the defects that locally change the sign of the uniaxial anisotropy in the crystal can lead to the energetic favorability of 0° domain walls, as well as to their generation in the presence of excitations in the system [11]. In this work, we have considered the excitation conditions of localized high-amplitude nonlinear waves in the region of two planar magnetic inclusions.…”

“…It is also known that, in these systems, apart from conventional linear excitations, namely, spin waves, there are nonlinear excitations, such as, for example, breathers [11]. The magnetic inhomogeneities generated on defects are frequently described as the 0° domain walls (or magnetic soliton) [3,12].…”