以飛秒光譜探測系統研究釔錳氧薄膜之超快動力學

Abstract

本篇論文中，利用脈衝雷射蒸鍍系統成長二種不同結構的高純相釔錳氧化合物薄膜YMnO3：六角晶系和正交晶系；我們也對這些薄膜個別地利用X光繞射、X光吸收光譜、磁化率等做量測，去了解晶體結構、電子結構、電性與磁性等之基本物理特性。並且使用飛秒激發探測光譜技術量測兩者之超快動力行為。藉由這些分析,來比較不同結構薄膜的差異性，並解釋其電子自旋和晶格之間的耦合行為，以進一步了解釔錳氧多鐵材料之物理機制。

In this thesis, pure hexagonal and orthorhombic phases of YMnO3 (h-YMO and o-YMO) thin films were prepared by pulsed laser deposition. The basic characterizations of these YMnO3 films, include the crystal structure, electric structure, magnetic properties, were measured by X-ray diffraction, X-ray absorption spectrum and magnetization, respectively. In addition the ultrafast dynamics of both samples were also measured by a femtosecond pump-probe technique. According to these analyses, we can compare the different properties between the h-YMO and o-YMO films, explain the coupling among electron, spin, and lattice, and further understand the physical mechanisms of the multiferroic behavior of the YMO material.