铁磁性材料在热平衡下依旧存在自发的磁化涨落，产生相应的磁性噪声。 对此噪声的探测和研究有助于我们理解磁相互作用以及磁动力学过程并建 立相应的理论模型。本工作结合克尔显微镜、磁光克尔效应和自旋噪声谱三 种测量手段，研究了铁磁性薄膜材料 Co20Fe60B20 在自旋重取向转变点附近 的磁性噪声。基于搭建的克尔显微光路，本实验观察了样品在自旋重取向转 变过程中磁畴随温度和垂直膜面方向磁场的变化，并在对应的温度下开展磁 光克尔效应测量得到了相应的磁滞回线，之后结合磁畴成像的结果进行了分 析和讨论。然后我们在前述基础上开展了自旋噪声谱测量，得到了不同温 度和磁场下克尔椭偏率的功率谱密度和磁化噪声功率，并以磁化噪声功率 作为磁性噪声的参考指标探究了磁性噪声随温度和磁场的变化。最后我们 在320 −330 K 的温度范围内观察到了磁性 Skyrmion 的存在，并结合对应温度 下磁化噪声功率随磁场的变化曲线进行了印证，更进一步的定量分析和计算 有待后续的推进和展开。

Ferromagnetic materials still have spontaneous magnetization fluctuations in thermal equilibrium, resulting in magnetization noise. The detection and study of this noise will help us to understand magnetic interaction and magnetodynamic processes and to build theoretical models. In this experiment, we investigate the magnetization noise of the thin ferromagnetic film Co20Fe60B20 around its spin-reorientation transition (SRT) by Kerr microscope, Magneto-optical Kerr effect (MOKE) measurement and spin noise spectroscopy (SNS). Based on Kerr microoptical, we observe the variation of magnetic domains with the temperature and magnetic field in the direction of the perpendicular membrane surface during SRT. And we measure magnetic hysteresis loops at the same temperature by MOKE measurement, with the analysis in combination with the magnetic domain imaging. The power spectral density and integral noise of Kerr ellipsometry are measured by SNS. The variation of the magnetization noise with temperature and magnetic field is investigated by using the integral noise as a reference index. Finally, the magnetic skyrmion was observed in a wide temperature range from 320 K to 330 K, which is confirmed by variation curves of integral noise with magnetic field. Further quantitative analysis and calculation need to promoted and developed.