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arXiv · 1411.7762

Topological Charge Analysis of Ultrafast Single Skyrmion Creation

Gen Yin·Yufan Li·Lingyao Kong·Roger K. Lake·C. L. Chien·Jiadong Zang
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Abstract

Magnetic skyrmions are topologically non-trivial spin textures of potential interest for future information storage applications, and for such purposes, the control and understanding of single skyrmion creation is required. A scheme is analyzed to create single N\'{e}el-type and Bloch-type skyrmions in helimagnetic thin films utilizing the dynamical excitations induced by the Oersted field and the spin transfer torque given by a vertically injected spin-polarized current. A topological charge analysis using a lattice version of the topological charge provides insight into the locally triggered transition from a trivial to a non-trivial topological spin texture of the N\'{e}el or Bloch type skyrmion. The topological protection of the magnetic skyrmion is determined by the symmetric Heisenberg exchange energy. The critical switching current density is $\sim10^{7}\thinspace\textrm{A/cm}^{2}$, which decreases with the easy-plane type uniaxial anisotropy and thermal fluctuations. In-plane spin polarization of the injected current performs better than out-of-plane polarization, and it provides ultrafast switching times (within 100 ps) and reliable switching outcomes.

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Gen Yin, Yufan Li, Lingyao Kong, Roger K. Lake, C. L. Chien, Jiadong Zang. 2014-11-28. Topological Charge Analysis of Ultrafast Single Skyrmion Creation. https://doi.org/10.1103/physrevb.93.174403

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