The spin Hall effect appears in nature in two forms. Its intrinsic form is highly dependent on the crystal symmetry while its extrinsic form stems from impurity scattering. Its efficiency is defined by the spin Hall angle, [Formula: see text], and has profound impact on spintronic technologies. However, an accurate measurement of [Formula: see text] is not straightforward nor the identification of its origin. In this work, we apply a spin-torque driven ferromagnetic resonance method that is probed in two different ways, optically and electrically, to study the dependence of [Formula: see text] in the crystallographic direction in epitaxial Al2O3/Pt (111), MgO(110)/Pt (110), and MgO(001)/Pt (001) films. We show that the electrical technique is limited in its ability to accurately quantify [Formula: see text] at high current densities, and in some cases, it may even result in erroneous [Formula: see text] values. Such cases include films that exhibit a large inhomogeneous broadening. We find that [Formula: see text] is strongly affected by the crystallographic direction. Our study extends the understanding of one of the most commonly used methods for the exploration of the spin Hall effect.

中文翻译：

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外延 Pt 薄膜中自旋霍尔角的晶体学依赖性：自旋力矩铁磁共振技术的光学和电学检测比较

自旋霍尔效应在自然界中以两种形式出现。其内在形式高度依赖于晶体对称性，而其外在形式则源于杂质散射。它的效率由自旋霍尔角定义，[公式：见文本]，对自旋电子技术具有深远的影响。然而，[公式：见正文]的准确测量并不简单，也无法确定其来源。在这项工作中，我们应用了一种自旋力矩驱动的铁磁共振方法，该方法以光学和电学两种不同的方式进行探测，以研究 [公式：见文本] 在外延 Al 的结晶方向上的依赖性2个欧3个/Pt (111)、MgO(110)/Pt (110) 和 MgO(001)/Pt (001) 薄膜。我们表明，电气技术在高电流密度下准确量化 [公式：见文本] 的能力有限，在某些情况下，它甚至可能导致错误的 [公式：见文本] 值。这种情况包括表现出大的不均匀展宽的薄膜。我们发现 [Formula: see text] 受结晶方向的强烈影响。我们的研究扩展了对探索自旋霍尔效应最常用方法之一的理解。