In this work, undoped semiconductors, germanium (Ge) and germanium tin (GeSn), were grown on ferrimagnetic insulator yttrium iron garnet (YIG) thin films using ultra-high vacuum molecular beam epitaxy. The crystallinity of the structure was determined from x-ray diffraction and high-resolution transmission electron microscopy combined with energy dispersive x-ray spectroscopy. Both spin pumping and inverse spin Hall effects (ISHEs) of YIG/Ge and YIG/GeSn heterojunctions have been investigated with the help of broadband ferromagnetic resonance (FMR). We observe that the spin mixing conductances of YIG/Ge (60 nm) and YIG/GeSn (60 nm) are 5.4 × 1018 m−2 and 7.2 × 1018 m−2, respectively, responsible for giant spin current injection. Furthermore, it is found that spin pumping injects giant spin current from ferrimagnetic YIG into the Ge semiconductor. The infrared laser modulated ISHE was examined using heavy metal platinum as a spin current collector. Also, it has been noted that the variation in the power of laser irradiation significantly changed the ISHE voltage of YIG/Ge/Pt spin junctions, saturated magnetization, FMR linewidth, and Gilbert damping parameter of YIG, which could be attributed to the laser-induced thermal effect. The outcomes from this study are promising for the development of Ge-based spintronic and magnonic devices.

中文翻译：

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钇铁石榴石/锗异质结中的自旋泵浦和激光调制反自旋霍尔效应

在这项工作中，使用超高真空分子束外延在亚铁磁绝缘体钇铁石榴石 (YIG) 薄膜上生长未掺杂的半导体锗 (Ge) 和锗锡 (GeSn)。该结构的结晶度由 X 射线衍射和高分辨率透射电子显微镜结合能量色散 X 射线光谱法确定。已经在宽带铁磁共振 (FMR) 的帮助下研究了 YIG/Ge 和 YIG/GeSn 异质结的自旋泵浦和反自旋霍尔效应 (ISHE)。我们观察到 YIG/Ge (60 nm) 和 YIG/GeSn (60 nm) 的自旋混合电导分别为 5.4 × 1018 m-2 和 7.2 × 1018 m-2，负责巨自旋电流注入。此外，发现自旋泵浦将来自亚铁磁 YIG 的巨大自旋电流注入 Ge 半导体。使用重金属铂作为自旋集流体检查红外激光调制的ISHE。此外，已经注意到激光照射功率的变化显着改变了 YIG/Ge/Pt 自旋结的 ISHE 电压、饱和磁化强度、FMR 线宽和 YIG 的吉尔伯特阻尼参数，这可能归因于激光-诱导热效应。这项研究的结果有希望开发基于 Ge 的自旋电子和磁子器件。这可能归因于激光诱导的热效应。这项研究的结果有希望开发基于 Ge 的自旋电子和磁子器件。这可能归因于激光诱导的热效应。这项研究的结果有希望开发基于 Ge 的自旋电子和磁子器件。