论文标题
轴向对称的自旋纳米线中的域壁运动
Domain wall motion in axially symmetric spintronic nanowires
论文作者
论文摘要
本文涉及纳米线中磁性域壁（DWS）的动力学，作为对经典Landau-lifschitz-gilbert方程的解决方案，该方程是由典型的非变化slonczewski术语增强的。以应用的场和自旋极化为主要参数，我们在轴向对称设置中分析和数值上研究动态稳定性以及选择机制。关于DWS的渐近状态的稳定性，我们区分了双轴（稳定）和单位稳定（一个不稳定的，一个稳定的）参数状态。在双态性方面，我们扩展了一个明确的进攻溶液家族的已知稳定性结果，并确定了施加的场和静态DWS的自旋极化的关系。我们验证这个家庭对单一稳定政权的对流不稳定，从而形成了所谓的推动前线，然后完全不稳定。在单一的制度中，我们为更通用的矩阵运算符的所谓绝对光谱提供了明确的公式。这使我们能够将翻译和旋转对称性与点绿色函数的奇异性位置联系起来。因此，我们确定了DWS的渐近速度和频率的线性选择机制，并通过长期数值模拟来证实它们。所有这些结果包括轴向对称的Landau-lifschitz-gilbert方程。
This article is concerned with the dynamics of magnetic domain walls (DWs) in nanowires as solutions to the classical Landau-Lifschitz-Gilbert equation augmented by a typically non-variational Slonczewski term for spin-torque effects. Taking applied field and spin-polarization as the primary parameters, we study dynamic stability as well as selection mechanisms analytically and numerically in an axially symmetric setting. Concerning the stability of the DWs' asymptotic states, we distinguish the bistable (both stable) and the monostable (one unstable, one stable) parameter regime. In the bistable regime, we extend known stability results of an explicit family of precessing solutions and identify a relation of applied field and spin-polarization for standing DWs. We verify that this family is convectively unstable into the monostable regime, thus forming so-called pushed fronts, before turning absolutely unstable. In the monostable regime, we present explicit formulas for the so-called absolute spectrum of more general matrix operators. This allows us to relate translation and rotation symmetries to the position of the singularities of the pointwise Green's function. Thereby, we determine the linear selection mechanism for the asymptotic velocity and frequency of DWs and corroborate these by long-time numerical simulations. All these results include the axially symmetric Landau-Lifschitz-Gilbert equation.
