鑭鈣錳氧薄膜的兆赫輻射時析頻譜研究

Abstract

在本論文中，利用本研究群所建立之兆赫茲波段的時域頻譜量測分析技術，研究鈣鈦礦結構磁性薄膜鑭鈣錳氧在此頻段下的電磁特性，利用量測結果與理論分析可獲得溫度與頻率相關之薄膜材料之複數折射率，並進一步求得材料之介電係數、光學電導率，其中鑭鈣錳氧薄膜在室溫降至低溫的過程中有絕緣金屬的相變，其中低溫的金屬行為我們試著使用Drude- Model來做數學擬合，我們可以得到粒子的散射率與電漿頻率等物理參數。

The electromagnetic properties of La0.7Ca0.3MnO3 (LCMO) thin films at THz frequencies have been studied by Terahertz-Time Domain Spectroscopy (THz-TDS). The THz electric fields transmitted through the LCMO thin films at various temperatures were measured. The temperature and frequency dependence of the complex index of refraction, dielectric function and conductivity can be determined from the complex transmittance and Fresnel equation. In addition, we carefully analyzed the data of dielectric constant spectra of LCMO thin films by a simple Drude model including the plasma frequency and the scattering rate as parameters.