Driving spin systems to states far from equilibrium is indispensable in investigations of functional nonlinearities of antiferromagnets for spintronics. So far, it has been shown that electric-field pulses in the spectral region from the visible to the terahertz range can be used to induce ultrafast switching between different spin states. Here we demonstrate that a multicycle terahertz magnetic-field pulse can be used to induce non-thermal spin switching in antiferromagnets. When a strong pulse is applied to Sm_0.7Er_0.3FeO₃, the magnetic order parameter is first driven away from the barrier between the two potential minima of this antiferromagnet and then, in the subsequent inertial motion towards the opposite direction, it crosses the barrier. Our analysis reveals that the initial motion is driven by a dynamical modification of the magnetic potential, and this modification is enhanced through coupling between the two magnon modes.

在研究自旋电子学的反铁磁体的功能非线性时，将自旋系统驱动到远离平衡的状态是必不可少的。到目前为止，已经表明，从可见光到太赫兹范围的光谱区域中的电场脉冲可用于在不同自旋状态之间感应超快切换。在这里，我们证明了多周期太赫兹磁场脉冲可用于在反铁磁体中感应非热自旋切换。当对 Sm_0.7Er_0.3FeO₃ 施加强脉冲时，磁序参数首先从该反铁磁体的两个电位最小值之间的势垒中被驱离，然后在随后的向相反方向的惯性运动中，它穿过势垒。我们的分析表明，初始运动是由磁势的动力学修改驱动的，并且这种修改是通过两种磁振子模式之间的耦合来增强的。