Low-power continuous-wave all-optical magnetic switching in ferromagnetic nanoarrays
Low-power continuous-wave all-optical magnetic switching in ferromagnetic nanoarrays
复制标题
铁磁纳米阵列中的低功耗连续波全光磁开关
DOI：
10.1016/j.xcrp.2023.101291
复制
发表时间：
2023
影响因子：
8.9
通讯作者：
Stenning K
中科院分区：
文献类型：
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作者：
Stenning K
全光磁开关有望在无磁场的情况下实现超快磁化控制。现有方案通常需要耗电的飞秒脉冲激光器和复杂的磁性材料。在这里，我们使用聚焦的低功率、线偏振连续波激光器演示了具有亚衍射极限尺寸的简单铁磁纳米磁体（NiFe、NiFe）中的确定性全光磁开关。孤立的纳米磁体在一系列尺寸、激光波长和功率之间切换。所有方形几何人工自旋冰顶点配置均以低功率（2.74 mW）写入。通常，线偏振光的切换是对称禁止的；在这里，激光光斑的尺寸与纳米磁体相似，产生取决于纳米岛光斑位移的吸收分布。我们将确定性切换归因于这种不对称吸收的瞬态动力学。在 Co 或 Ni 纳米结构中没有观察到转换，这表明 NiFe 的多物种性质发挥了作用。这些结果带来了廉价、低功耗、光控设备，对数据存储、神经形态计算和可重构磁振子产生影响。
All-optical magnetic switching promises ultrafast magnetization control without a magnetic field. Existing schemes typically require power-hungry femtosecond-pulsed lasers and complex magnetic materials. Here, we demonstrate deterministic, all-optical magnetic switching in simple ferromagnetic nanomagnets (NiFe, NiFe) with sub-diffraction limit dimensions using a focused low-power, linearly polarized continuous-wave laser. Isolated nanomagnets are switched across a range of dimensions, laser wavelengths, and powers. All square-geometry artificial spin ice vertex configurations are written at low powers (2.74 mW). Usually, switching with linearly polarized light is symmetry forbidden; here, the laser spot has a similar size to the nanomagnets, producing an absorption distribution that depends on the nanoisland-spot displacement. We attribute the deterministic switching to the transient dynamics of this asymmetric absorption. No switching is observed in Co or Ni nanostructures, suggesting the multi-species nature of NiFe plays a role. These results usher in inexpensive, low-power, optically controlled devices with impact across data storage, neuromorphic computation, and reconfigurable magnonics.