We report an observation of a giant magneto-optical (MO) effect quadratic in magnetization (Cotton-Mouton effect) in a 50 nm thick layer of yttrium-iron garnet (YIG). By a combined theoretical and experimental approach, we managed to quantify both linear and quadratic MO effects in the studied material. We show that the quadratic MO signal in the thin YIG film can exceed the linear MO response, reaching values of 450 μrad that are comparable with Heusler alloys or ferromagnetic semiconductors. This relative enhancement of the quadratic MO response relative to the linear MO response is attributed to antiferromagnetic coupling of two Fe sublattices. Furthermore, we demonstrate that a proper choice of experimental conditions, particularly with respect to the used wavelength, is crucial for optimization of the quadratic MO effect, which can be used very efficiently for magnetometry measurement.

中文翻译：

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用于灵敏磁力测量实验的 Y3Fe5O12 薄膜的巨大二次磁光响应

我们报告了在 50 nm 厚的钇铁石榴石 (YIG) 层中观察到的磁化 (Cotton-Mouton 效应) 的巨磁光 (MO) 效应。通过结合理论和实验方法，我们设法量化了研究材料中的线性和二次 MO 效应。我们表明，薄 YIG 薄膜中的二次 MO 信号可以超过线性 MO 响应，达到 450 μrad 的值，与 Heusler 合金或铁磁半导体相当。二次 MO 响应相对于线性 MO 响应的这种相对增强归因于两个 Fe 亚晶格的反铁磁耦合。此外，我们证明了适当的实验条件选择，尤其是在使用的波长方面，对于优化二次MO效应至关重要，