Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/9793
標題: [Pt(2.8nm)/Co(t nm)]4 /NiO(42nm) /SiO2 奈米多層膜系 統的第一原理分析
First-Principles Analysis of Co/Pt multilayers
作者: 王宏斌
Wang, Hung-Pin
關鍵字: multilayer;多層膜;TEM;GGA;穿透式電子顯微鏡;廣義梯度近似法
出版社: 材料科學與工程學系
摘要: 
我們發現在[Pt(2.8nm)/Co(t nm)]4 /NiO(42nm)) /SiO2 的多層膜系統中鐵磁性的磁易軸,隨Co 厚度減少而由平行界面變成垂直界面。在Co/Pt 多層膜系統中,垂直異相性並非起因於多層膜結構,而是合金相之CoPtL10 結構與disorder 結構,我們發現在沉積NiO 的同時以不同能量去轟擊,形成不同之NiO 接合Co 結構會造成Co/Pt 合金相。當Co 厚度為1.2nm 時的多層膜構造,利用穿透式電子顯微鏡分析,發現Co 的(0001)面與Pt 的(111)面相連接,並有垂直磁異向性的趨勢。我們進一步利用Multislice method 、HRTEM ( high resolution transmission electron microscope)影像、繞射平面之間的夾角,三者作交叉分析,進而找出原子的排列情形與界面接合形式。再進一步鍵入實際的結構到從頭起算法模擬程式(Vienna ab-initio Simulation Package; VASP ),並利用根據廣
義梯度近似(generalized gradient approximation; GGA)來研究不同位置的Co 與Pt 之電子結構、磁性質與總能等。

We find the easy axis of Co/Pt multilayer perpendicular to the plane when the thickness of Co layer is 1.2nm.We found perpendicular anisotropy was due to CoPt L10 phase and CoPt disorder phase in Co/Pt multilayer system. By detailed simulation of a structure mapped onto high resolution transmission electron microscope (HRTEM) image patterns, both the results from experiments and simulations are compared than the atomic positions were identified. The detailed atomic arrangements of materials specimen can be fed into the first-principles calculations. We study the atomic structure, electrical property and magnetic property of interface in Co/Pt multilayers according to the local density functional approximation (LDA)、density functional theory (DFT) and generalized gradient approximation (GGA) following the Vienna Ab-initio Simulation Package (VASP) code.
URI: http://hdl.handle.net/11455/9793
Appears in Collections:材料科學與工程學系

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