Gomonay O, Jungwirth T, Sinova J
Institut für Physik, Johannes Gutenberg Universität Mainz, D-55099 Mainz, Germany.
National Technical University of Ukraine "KPI", 03056 Kyiv, Ukraine.
Phys Rev Lett. 2016 Jul 1;117(1):017202. doi: 10.1103/PhysRevLett.117.017202. Epub 2016 Jun 29.
We demonstrate the possibility to drive an antiferromagnetic domain wall at high velocities by fieldlike Néel spin-orbit torques. Such torques arise from current-induced local fields that alternate their orientation on each sublattice of the antiferromagnet and whose orientation depends primarily on the current direction, giving them their fieldlike character. The domain wall velocities that can be achieved by this mechanism are 2 orders of magnitude greater than the ones in ferromagnets. This arises from the efficiency of the staggered spin-orbit fields to couple to the order parameter and from the exchange-enhanced phenomena in antiferromagnetic texture dynamics, which leads to a low domain wall effective mass and the absence of a Walker breakdown limit. In addition, because of its nature, the staggered spin-orbit field can lift the degeneracy between two 180° rotated states in a collinear antiferromagnet, and it provides a force that can move such walls and control the switching of the states.
我们证明了通过类场奈尔自旋轨道转矩以高速驱动反铁磁畴壁的可能性。这种转矩源于电流诱导的局部场，该局部场在反铁磁体的每个亚晶格上交替其取向，并且其取向主要取决于电流方向，赋予它们类场特性。通过这种机制可实现的畴壁速度比铁磁体中的速度大2个数量级。这源于交错自旋轨道场与序参量耦合的效率以及反铁磁纹理动力学中的交换增强现象，这导致低畴壁有效质量并且不存在沃克击穿极限。此外，由于其性质，交错自旋轨道场可以消除共线反铁磁体中两个180°旋转状态之间的简并性，并且它提供了一种可以移动此类畴壁并控制状态切换的力。
