多鐵材料材料具有多元的有序參量共存以及強烈的電磁耦合，我們甚至可以利用不同的參數來調控這些物理特性，在這些因素下使得近年來多鐵材料備受物理學界矚目。在2012年，SmFeO3(SFO)被預測為一種新型的室溫多鐵材料，在尼爾溫度(Neel Temperature, TN)低於670 K時，它表現出顯著的反鐵磁性和磁化現象，此現象是由於自旋軌道耦合驅動的Dzyaloshinskii-Moriya交互作用所產生。然而，關於單晶SFO是否具有鐵電性仍具有很大的爭論。在此研究中，我們計畫利用不同的晶格常數基板(LaAlO3, NdGaO3)來製成SFO薄膜，藉此調控SFO所受到的應力。目前在製程上，我們已完成利用脈衝雷射沉積系統(Pulse Laser Deposition) SFO部分薄膜的成長；為了確定SFO薄膜的磊晶高品質，我們也已藉由原子力顯微鏡(Atomic force microscopy)來探測薄膜表面，確認SFO是層層磊晶的成長性質(Layer-by-Layer growth) ，並進一步透過同步輻射中心的高解析度XRD來量測量這兩種SFO薄膜系統上的應力。確認好薄膜品質以及應力後，我們使用壓電力顯微鏡(Piezoresponse force microscopy)間接地來探討SFO的鐵電特性，在電滯曲線以及極化的翻轉和寫入都有正向的結果。未來將會引入第一原理計算與X射線吸收光譜(X-ray absorption spectroscopy)來研究這些不同SFO薄膜的電子結構，以釐清此一謎團。

Multiferroic materials have caught significant attention in the last decade because of its interesting properties and intriguing coupling between different order parameters. SmFeO3(SFO) was predicted as a new type of room-temperature multiferroic system in 2012. It exhibits anti-ferromagnetism and significant magnetization below TN ∼ 670 K resulting from Dzyaloshinskii-Moriya interaction driven by spin orbital coupling. However, the existence of ferroelectricity of SFO single crystal is still under debate. In this work, we process the growth of SFO thin films on various single crystalline substrates (LaAlO3 and NdGaO3) which has rarely been done hitherto. An elegant combination of multiple characterizations has been conducted to identify the ferroic order parameters of SFO thin films. Atomic force microscopy is used to check the surface of the thin film and certify the layer-by-layer growth nature. The interfacial strains between two different oxide materials are calculated by using high resolution XRD. X-ray absorption spectroscopy is used to determine local geometric and electronic structures. Piezoresponse force microscopy has clearly identified the ferroelectricity of SFO grown on NdGaO3 substrate. The information pileup reveals a new room temperature single-phase multiferroic system.

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