本論文主要是研究超巨磁阻薄膜( La0.7Sr0.3MnO3,一般簡稱LSMO )在不同溫度下的光學性質與載子行為。實驗主要分為兩大部分，第一部份是利用兆赫波頻譜量測技術與薄膜穿透頻譜分析模型來研究超巨磁阻薄膜在不同溫度狀態下的光學常數( ex.折射率、吸收係數，介電常數 )，同時由Drude Model來求出薄膜的電導率。這部份的實驗結果我們可以分析出超巨磁阻薄膜折射率值在兆赫波波段內(0.1~ 1.8 THz)都约在15~65的範圍。第二部份主要是是針對超巨磁阻薄膜的非平衡動力學行為做理論與實驗上的分析，就理論方面我們是採用三溫模型(Three temperature model)來分析實驗結果，而在這部份的實驗中我們採用了兩種量測技術，分別是時間解析激發-探測反射光量測方式(Time-resolved photoreflecitivity，簡稱PR)與光激發-兆赫波探測穿透量測方式(optical pump-THz probe，OPTP)，在PR的實驗結果中我們解析出了五個階段的鬆弛時間(relaxation time)，同樣地，從OPTP的變溫實驗結果中亦得到了相似的載子暫態反應行為。

In the thesis, we have investigated the carrier dynamics in films of colossal magnetoresistance (CMR ,La0.7Sr0.3MnO3) .First ,we have measured the transmission THz time domain spectroscopy to obtain index of refract、power absorption，dielectric constant of the CMR film and then used Drude Model to estimate conductivity of the film. From these data, the index of refract of colossal magnetoresistance film in THz range (0.1~ 1.8 THz)is determined in the range of 15~65 .
To understand the dynamic behaviors , we have measured time-resolved photoreflecitivity (PR) and optical pump-THz probe (OPTP) of the film .By using three temperature model to analysis these results , we can obtain the dynamics process of electron-electron interactions、electron-lattice interactions and spin-lattice interactions .From these PR data, we find five relaxation times and we can explain three of them . Similarly, from these OPTP datum we observe similar phenomenon.

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