氧化物的導電機制以及氧化物複合材料之間介面的特殊物理性質是近年來炙手可熱的研究議題。本研究針對鐵酸鉍(BiFeO3)和鈷鐵氧體(CoFe2O4)複合式材料探討比較其介面的導電機制，使用導電式原子力顯微鏡(conductive-Atomic Force Microscopy)觀察微觀結構下的電流分布以及定點電流-電壓關係，並使用顯微拉曼及光激發光譜儀量測螢光光譜獲得缺陷能級來分析其導電機制。量測結果顯示於鐵酸鉍和鈷鐵氧體介面處具有不同於鐵酸鉍與鈷鐵氧體本身的導電性質，並且可藉由外加磁場、照雷射光、施加電壓等操控手法改變其導電性質，再輔以螢光光譜得到樣品缺陷能級的變化，探討樣品介面特殊導電性的可能機制。

The special feature of the interface between the oxide composite materials and conduction at the interface had attracted great interests in recent years. In this study, we investigated the conductivity mechanism in magneto-electric nano-composites composed of multiferroic BiFeO3 (BFO) and ferrite CoFe2O4 (CFO). By using conductive atomic force microscopy (c-AFM), the current distribution and the barrier for carrier transportation were analyzed. Meanwhile, the defect levels were observed by using photoluminescence spectrum. The results show that the BFO-CFO interface is more conductive than the matrices, and the conduction states are affected by external magnetic fields, irradiated laser light, and applied voltages. The conduction mechanism at the interface is thus discussed by measuring the variation of photoluminescence, which shows changes in defect levels, under different external parameters.

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