Electrical Switching of the Vortex Core
A magnetic vortex is a curling magnetic structure realized in a ferromagnetic disk, which is a promising candidate for a memory cell for future non-volatile data-storage devices. Thus, an understanding of the stability and dynamical behavior of the magnetic vortex is a major requirement for developing magnetic data-storage technology. Since the publication of experimental proof for the existence of a nanometer-scale core with out-of-plane magnetization in a magnetic vortex, the dynamics of vortices have been investigated intensively. However, a way to electrically control the core magnetization, which is a key for constructing a vortex-core memory, has been lacking. Here, we demonstrate the electrical switching of the core magnetization by using the current-driven resonant dynamics of the vortex; the core switching is triggered by a strong dynamic field that is produced locally by a rotational core motion at a high speed of several hundred meters per second (Figure). Efficient switching of the vortex core without magnetic-field application is achieved owing to resonance. This opens up the potentiality of a simple magnetic disk as a building block for spintronic devices such as a memory cell where the bit data is stored as the direction of the nanometer-scale core magnetization.
Figure: Perspective view of the magnetization with a moving vortex structure. After the electric pulse is applied to the initial status (a), the vortex core starts to rotate and finally reverses its direction in 20 ns (b-f).
“Electrical switching of the vortex core in a magnetic disk ”
by K. Yamada, S. Kasai, Y. Nakatani, K, Kobayashi, H. Kohno, A. Thiaville, and T. Ono
Nature Materials, 6, 269 (2007).