Nanocavity-Mediated Fast Magnetic Vortex Core In-Situ Switching by Local Magnetic Field

Abstract

Fast in situ switching of magnetic vortex core in a ferromagnetic nanodisk assisted by a nanocavity, with diameter comparable to the dimension of a vortex core, is systematically investigated by changing the strength as well as the diameter of the effective circular region of the applied magnetic field. By applying a local magnetic field within a small area at the nanodisk center, fast switching time of about 35 ps is achieved with relatively low field strength (70 mT) which is beneficial for fast data reading and writing. The reason for this phenomenon is that the magnetic spins around the nanocavity is aligned along the cavity wall due to the shape anisotropy when the perpendicular field is applied, which deepens the dip around the vortex core, and thus facilitates the vortex core switching.

Asymmetric scattering behaviors of spin wave dependent on magnetic vortex chirality

“…[25] Recently, it has been found that behaviors of SW propagation become richer and easier to be controlled with introduction of topological spin textures, [4] due to the fact that the spin texture exhibits structurally stable soliton-like dynamic behavior, [26,27] which can produce SWs when excited by an external field and influence the behavior of SWs as they propagate. [27][28][29] Among various spin textures, the magnetic vortex not only effectively excites SWs [30,31] through the gyromotion, [32,33] azimuth mode motion [34,35] or radial mode motion [36] of its core, but also controls the SW propagation behaviors by switching its chirality. [30] The vortex has two chirality with right and left handedness, [37] which are characterized by the circulation sense of the in-plane circling spins [c = −1 for clockwise (CW), c = 1 for counterclockwise (CCW)] and the polarity of the vortex core (VC) (p = 1 for upward core, p = −1 for downward core).…”