Extreme Domain Wall Speeds under Ultrafast Optical Excitation
Extreme Domain Wall Speeds under Ultrafast Optical Excitation
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DOI：
10.1103/physrevlett.131.256702
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发表时间：
2023-12-19
影响因子：
8.6
通讯作者：
Silva，Thomas J.
中科院分区：
文献类型：
--
作者：
Jangid，Rahul;Hagstrom，Nanna Zhou;Silva，Thomas J.
时间分辨超快 EUV 磁散射用于通过光学激发具有纳米级迷宫磁畴图案的磁性样品来测试最近对磁畴壁速度的预测。与磁化淬灭相比，在明显不同的时间尺度上观察到衍射图样的超快畸变。衍射图案畸变显示出与激光注量的阈值依赖性，这在磁化淬灭中未见，与具有钉扎位点的磁畴壁运动的图片一致。在模拟的支持下，我们表明高度弯曲的畴壁的速度可以解释实验数据。虽然我们的数据与局部极端非平衡壁速度的预测一致，但它与理论的细节不同，这表明需要额外的机制来充分理解这些效应。
Time-resolved ultrafast EUV magnetic scattering was used to test a recent prediction ofdomain wall speeds by optically exciting a magnetic sample with a nanoscale labyrinthine domain pattern. Ultrafast distortion of the diffraction pattern was observed at markedly different timescales compared to the magnetization quenching. The diffraction pattern distortion shows a threshold dependence with laser fluence, not seen for magnetization quenching, consistent with a picture of domain wall motion with pinning sites. Supported by simulations, we show that a speed offor highly curved domain walls can explain the experimental data. While our data agree with the prediction of extreme, nonequilibrium wall speeds locally, it differs from the details of the theory, suggesting that additional mechanisms are required to fully understand these effects.