光控磁性研究對於磁性儲存技術等應用具有極大重要性，光調控不僅可以以聚焦程度控制照光區域範圍，且調控過程為非接觸式，在製程上有一定程度方便性。本篇研究主要以光為調控物性手法，在室溫環境下控制鈷鐵氧體(CoFe2O4)磊晶薄膜的磁疇結構與磁矩方向。本研究利用磁力顯微鏡(Magnetic Force Microscope, MFM)觀測照光前後的CFO薄膜磁疇結構變化，另外也透過表面電位顯微鏡(Kelvin Force Microscope, KFM)與拉曼光譜來幫助探討照光引起磁性變化的機制。

透過改變光的偏振與波長、照光強度與時間、樣品膜厚等變因，我們推論光致磁性變化機制是由熱效應主導，並經由拉曼光譜估算出照光引起的升溫效果。另外透過KFM，我們發現特定照光條件下會發生發生表面電荷累積情形，但經由實驗證明，表面電荷與磁性變化沒有因果關係。最後更進一步討論在外加磁場下的光致磁性變化，發現照光後的磁疇磁矩方向變化同時受到樣品初始磁化狀態與外加磁場影響。

Complex oxides have caught significant attention for the development of the next-generation electronic devices due to their versatile functionalities and the tunability via the external stimuli, such as electrical and magnetic fields. To broaden the application of complex oxides, the new pathway to control the physical properties is on demand. Cobalt ferrite (CoFe2O4), a ferrimagnetic inverse spinel, is potential in the application of magnetic storage device because of its high magnetization and coercivity. In this study, we introduce the optical method to control the magnetic domain configuration of CoFe2O4 thin film. We use not only magnetic force microscopy (MFM) to investigate the change of the magnetic state of the area illuminated by laser light but also Kelvin Force Microscope (KFM) and Raman spectroscopy to analyze the possible mechanisms behind the changes of magnetic properties induced by light illumination.

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