论文标题
超快速动力学的电流辅助Bloch点壁稳定机制
Mechanism of current-assisted Bloch-point wall stabilization for ultra fast dynamics
论文作者
论文摘要
在磁性柔软的圆柱纳米线中存在两种类型的域壁：横向涡流壁（TVW）和Bloch点壁（BPW）。后者有望防止通常的步行者崩溃，从而实现高域壁速。我们最近展示了[M。 Schöbitz\ etal，物理。莱特牧师。 123，217201（2019）]认为，与电流相关的先前被忽视的Oersted场是实验的关键，可以使用自旋转移稳定BPW并达到600 m/s的速度。在这里，我们通过微磁模拟和建模详细研究了这种情况。 BPW的方位角循环的切换以符合Oersted场的循环，以售价为$ 1/r^3 $（$ r $是电线半径），通过可能涉及Bloch点的成核和/或歼灭的机制。然后，域壁动力学仍然是步行者类型的，其速度在很大程度上由单独的转移扭矩确定。
Two types of domain walls exist in magnetically soft cylindrical nanowires: the transverse-vortex wall (TVW) and the Bloch-point wall (BPW). The latter is expected to prevent the usual Walker breakdown, and thus enable high domain wall speed. We showed recently [M. Schöbitz \etal, Phys. Rev. Lett. 123, 217201 (2019)] that the previously overlooked OErsted field associated with an electric current is a key in experiments to stabilize the BPW and reach speed above 600 m/s with spin-transfer. Here, we investigate in detail this situation with micromagnetic simulations and modeling. The switching of the azimuthal circulation of the BPW to match that of the OErsted field occurs above a threshold current scaling with $1/R^3$ ($R$ is the wire radius), through mechanisms that may involve the nucleation and/or annihilation of Bloch points. The domain wall dynamics then remains of a below-Walker type, with speed largely determined by spin-transfer torque alone.
