Tsai Tsung-Yu, Chen Tian-Yue, Wu Chun-Ting, Chan Hsin-I, Pai Chi-Feng
Department of Materials Science and Engineering, National Taiwan University, Taipei, 10617, Taiwan.
Department of Computer Science and Information Engineering, National Taiwan University, Taipei, 10617, Taiwan.
Sci Rep. 2018 Apr 4;8(1):5613. doi: 10.1038/s41598-018-23951-w.
Magneto-optical Kerr effect (MOKE) is an efficient approach to probe surface magnetization in thin film samples. Here we present a wide-field MOKE technique that adopts a Köhler illumination scheme to characterize the current-induced damping-like spin-orbit torque (DL-SOT) in micron-sized and unpatterned magnetic heterostructures with perpendicular magnetic anisotropy. Through a current-induced hysteresis loop shift analysis, we quantify the DL-SOT efficiency of a Ta-based heterostructure with bar-shaped geometry, Hall-cross geometry, and unpatterned geometry to be |ξ | ≈ 0.08. The proposed wide-field MOKE approach therefore provides an instant and direct characterization of DL-SOT, without the need of any further interpretation on electrical signals.
磁光克尔效应（MOKE）是探测薄膜样品表面磁化强度的一种有效方法。在此，我们展示了一种宽场MOKE技术，该技术采用柯勒照明方案来表征具有垂直磁各向异性的微米级无图案磁性异质结构中电流诱导的类阻尼自旋轨道矩（DL-SOT）。通过电流诱导的磁滞回线位移分析，我们将具有条形几何形状、霍尔交叉几何形状和无图案几何形状的钽基异质结构的DL-SOT效率量化为|ξ|≈0.08。因此，所提出的宽场MOKE方法能够对DL-SOT进行即时直接表征，而无需对电信号进行任何进一步解读。
