The Nucleation, Growth and Thermal Activation Depinning of Narrow Domain Wall L10 FePt Film from the Single Defect

Face-centered tetragonal L10 FePt film with long range ordering has recently attracted much attention due to its high magnetocrystalline anisotropy (Ku). Practical application of L10 FePt film fabrication has included reducing ordering temperature, perpendicular orientation, isolated grains or nanoparticles, and tunable hard magnetic properties. The above factors have been improved in many ways, for example, underlayers, intermediate layers, energetic ion irradiation, doping, gas formation during process and the ordered L10 CuAu, CrPt underlayer。The aim of this proposal can be divided into two parts. First year, the nucleation and growth mechanism of FePt single and (FePt/Ag) granular film were studied。To prove the linear (parabolic) growth and nucleation mode were dominated under lower and higher ordering temperature, respectively. Second year, artificial defects from patterning or defects from growth were used to study FePt narrow domain wall depinning by thermal activation.The measuring principle for traditional fire sensor is detecting the granule density, temperature, flameoptics characteristic which produces during the fire developed process. However, when these fire sensorsdetect the signal, the fire already developed quite seriously. Thus, the development of a sensor, which candetect all fires in their early stages is needed. It is known that decomposed gases (like CO, CO2, H2O), whichare emitted in the initial stage of a fire, were generated much earlier than smoke. However, carbon monoxideconcentration always keeps higher than environment during the fire developed process. Therefore, CO hasregard as a characteristic gas for early stage fire detection standard in many countries.In recent years, metal oxides have been used in CO detection in for many applications, such as SnO2,ZnO, Fe2O3, BaTiO3, TiO2, In2O3 and Zn2SnO4 semiconductor. Specific early fire detection is based on COhave to be detected fast in a low concentration (40ppm) and in a relatively low temperature range of60–10

高磁記錄密度及高磁能積異向性Fe-X (X=Pt, Co)濺鍍薄膜之製備及應用

本年度之研究重點為高能積薄膜磁鐵之製備，根據其製程方法及膜層結構設計又可分為(1)單晶垂直異向性L10 FePt 薄膜磁鐵之製備。(2)高能積(硬磁薄膜/軟磁團簇)之新型交換偶合膜製作。(3) 開發並試製MEMS 元件，例如微馬達之轉子。第(1)部份之研究是在證實高能積磁鐵確實能夠以薄膜之方式製作，因此可將薄膜磁鐵整合至微機電或奈米機電之系統中。該研究之目的希望將FePt 顆粒垂直的鑲埋於MgO 氧化物材料中或多孔性之氧化物基材，此時每一島狀L10 FePt 顆粒相當於孤立之單磁區粒子。該研究將以磊晶級之濺鍍法成長具有垂直異向性之FePt 膜，該法可有效控制奈米島狀FePt 顆粒之晶粒分佈度使其更加均勻，且有效調控晶粒間之距離。最終使得每顆FePt 顆粒如同單晶一般，這時磁化反轉行為將近似理想之同調旋轉頗具學術與應用價值。第(2)部份主要研究目的是希望製作出有別於傳統之硬磁/軟磁層交換偶合膜其中最主要之製程差異性在於Co 和Fe 之奈米團簇(nanocluster)之形成，須要於濺鍍系統中加入液態氮(LN2)冷卻之基板及高壓的載流氣體如Ar, He 來增加原子與氣體之碰撞次數使其有足夠之過飽合度生成奈米團簇，這樣子夠小的團簇均勻的散怖於FePt 的基地中，因其晶粒度夠

圖案化梯度界面Fe/FeB/FePtAg垂直記錄薄膜之磁性與微結構探討

Exchange coupled composite (ECC) media with perpendicular magnetization have demonstrated major advantage over conventional perpendicular media, including a reduction in the switching field for the same thermal stability and greater insensitivity to easy axis distribution. ECC seems to be a method of achieving an area density of several (Tbit/in2). The interface between hard- and soft -magnetic materials can be sharp or graded. In sharp interface, the ECC media contained only two regions with material parameters changing from the hard- to the soft- magnetic properties. In graded interface, the extended interface was introduced in between hard- and soft- magnetic layer and the material parameters were changed continuous.For first year, a soft/hard Fe/FePt (or Fe/B/FePtAg) bilayer with perpendicular magnetization was prepared on a glass substrate. Annealed Fe/FePt film allowed modification of the Fe/FePt sharp interface to Fe/(Fe-rich FePt)/FePt graded interface with rigid magnetization due to the nanoscale soft/hard interface coupling. The magnetization was reversed at a single switching field and interpreted by the two-spin model. When the annealed temperature of the Fe/FePt film increased, the reamnence magnetization decreased continuously but the out-of-plane coercivity increased obviously at 600-700oC which was interpreted by the graded magnetic anisotropy. The coercivity can be tuning in the exchange coupled composite film.For second year, block-copolymer (BCP) lithography was used to pattern the exchange coupled Fe/FePt and Fe/B/FePtAg film. Diblock copolymers PS-PMMA with different weight molecular and different volume fraction were used to fabricate sphere, cylinder nanostructure in matrix. The topography and microstructure were observed by SEM and TEM, respectively.An important characteristic of BCP lithography is that the domain dimensions scale with the molecular weight of the BCP, and therefore, the periodicity of the pattern can be controlled. The scalability of BCP lithography depends on the Flory-Huggins interaction parameter. The magnetization reversal process was discussed by the stoner-wohlfarth model and domain wall motion model.有關硬磁層(序化 Fe-Pt, Co-Pt)與軟磁層(Co/Pd, Fe, Co)間之垂直交互藕合作用(exchange coupling)近五年來被熱烈探討, 當然奈米晶硬軟磁相之交互藕合作用早在1990年代即由Kneller提出, 其目的在提高殘留磁化強度(remanence), 降低矯頑磁力(coercivity), 並於最佳之奈米晶軟磁相含量下, 提高磁體之磁能積值(magnetic energy product)。此外, 過去水平式記錄媒體亦利用層間藕合的作用, 例如, 反鐵藕合記錄媒體(antiferromagnetic coupled media), 層狀媒体(laminated media), 寫入輔助層技術(write assist layer technology)及交換藕合媒體(exchange spring layer(ESL))來改善寫入能力(writability), 穩定性(stability)及其它所有記錄效能。對於ESL和交換藕合複合(exchange coupled composite)媒體是本研究感興趣的, 利用硬軟磁層間之藕合來降低翻轉場(switching field)並且不犧牲其熱穩定性, 改善寫入能力其物理起源主要是利用媒體中不同磁性層間其磁晶各向異性能(Ku)之差異, 不同Ku將促使非均一場磁化反轉(nonuniform field reversal)模式的形成, 意指層間太強之藕合將無法形成非均一場磁化反轉, 藕合太弱則無軟磁層輔助硬磁層寫入之效果。第一年, Fe/FeB/FePtAg其硬磁與軟磁雙層薄膜, 其界面之交互藕合作用力與界面粗糙度(roughness), 界面擴散(diffusion), 及界面混相(intermixing)生成有很大關聯性。 該研究目的之一在探討硬磁/軟磁界面對於Fe/FePt雙層薄膜磁性之影響。首先, 製備平整界面(sharp interface)之SiO2/Fe/FeB/FePtAg雙層膜, FePt膜於高溫序化生成L10相後, 軟磁鐵層於室溫下鍍著且SiO2為之保護層且使得Fe晶粒呈現分隔狀態(isolate)。平整界面之互藕合作用力與軟磁層厚度相關, 因此其界面交互作用力或矯頑磁力(Hc)隨軟磁層厚度增加而減弱, 當軟磁層厚度小於臨界厚度時, 雙層膜呈現固定磁化之狀態(rigid magnetization), Fe層厚度大於臨界值則磁區壁於軟磁層中生成則呈現兩階段磁化反轉(two-steps magnetization reversal)。該研究目的希望找到軟磁層臨界厚度以及翻轉場(Hsw)隨Fe層厚度變化之趨勢。其次, 製備梯度界面(graded interface)之SiO2/Fe/FeB/FePtAg雙層膜, 將此雙層薄膜進行二次退火其溫度為200-700oC下持續一分鐘, 將形成Fe/Fe-rich FePtB/FePt 之三層交互藕合薄膜, 梯度界面區由富Fe之FePt相取代原來之Fe-FePt混相區(intermixing), 因此可維持固定磁化之磁滯曲線且矯頑磁力隨富鐵之FePt層厚度增加而增大。第二年, 本研究將以兩不互溶(immiscible)之聚合高分子聚苯乙烯(polystyrene)及聚甲基丙烯酸甲醛(PMMA)混合以形成PS-PMMA之共價鍵結(covalent bond), 由兩者之成份比可調控其基地相(matrix), 並於高於兩者玻璃轉換溫度(glass transition temperature)上退火使其形成長程有序之陣列結構，並曝以波長為185nm, 245nm之紫外光(ultraviolet, UV)使PS球鏈結(cross-linking)並使PMMA退化(degradable)，則形成均勻多孔之PS球模板, 再利用CF4, CHF3之氣體進行反應式乾式蝕刻(reactive ion etching)則成SiO2奈米柱。最後將FePt基之薄膜沉積於大面積之SiO2奈米柱上, 該柱則由由鏈狀聚合高分子模板經反應式蝕刻所產生。其目的希望FePt 於快速升溫退火製程後其點陣之分隔性仍佳, 且溝槽中之磁性物質極少並保有其垂直磁化之特性, 而磁性點陣之翻轉場分佈(switching field distribution)要小以避免鄰近位元之重覆寫入效應

Writable Composite Perpendicular Magnetic Recording Media Using FePt/PtSi/Fe-X(X=W, Mo, Nb, Cr) Exchange Coupled Island Film

本研究計畫主要目的是希望將高結晶異向性(Ku)的材料如FePt, SmCo5 運用於未來高密度之垂直磁記錄媒體。因為高結晶異向性材料可有效提高媒體的熱穩定性，假設在相同晶粒尺度下(V)，則KuV 值的提高等於是增加了位能障壁，使磁矩不至於受熱擾動(kBT)影響而造成記錄單元之混亂。但是該材料在應用上必須克服因高結晶異向性所形成過高的矯頑磁力值，才能配合目前寫頭所能寫入之外加場最大值。因此希望藉由複合式之垂直記錄媒體來降低硬/軟磁層之矯頑磁力，所謂複合式薄膜即是利用調變硬磁層和軟磁層間之交換藕合作用力來降低矯頑力，使用非磁性中間層並由其膜厚來控制藕合力也就是整體之矯頑力，使其大小在可寫之範圍內。但是該研究之目的將建立於島狀膜，顆粒膜，或奈米點陣的樣品上，主要在阻隔晶粒間的藕合作用以降低媒體之雜訊。接著將成長FePt/x/Fe(x=Au, Ag, Cu, Cr, Nb, Mo, Ta, Ru)多層膜，藉由中間層之膜厚控制及與相臨鐵磁層間之藕合力調變，將可得到一較低矯頑磁力藕合多層膜。此外本研究將探討FePt/x/Fe 之磁化反轉機制。對於島狀膜或顆粒膜而言，假設每一個島都是單磁區顆粒(single domain particle)則磁化反轉的行為將可由Stoner-Wohlfarth 的曲線來理解，每一磁性顆粒在外加場下的運動行為將以磁矩旋轉(rotation)為主導，因為沒有磁區壁。所以在外加場方向和磁化方向夾45 度時其矯頑磁力會最小。但是由實際製程上常得到不同尺寸之島結構，通常有二至三個磁區生成於顆粒中，因此磁區壁運動(domain wall motion)也必須考慮於磁化反轉行為中，加上島狀結構由於形狀(shape)或是表面(surface)所形成之磁異向性漲落亦會影響到磁化反轉行為

The Application of Spin Transfer Effect on Magnetic Data Storage

奈米磁記錄在奈米儲存技術中舉足輕重, 隨著記錄密度快速增加為配合垂直式記錄媒體未來的需求, 垂直式讀寫頭, 也就是電流垂直於膜面(current perpendicular to plane,CPP) 的相關研究也是必然的。因此本計畫將探討一關於電流垂直膜面巨磁阻之物理現象與機制, 當一自旋極化(spin polarized)電流通過一自由或是可受激(excitable)之磁性薄膜將使其磁化反轉, 也就是說在無外加磁場的情況下即可將磁化方向重新排列。該形式之磁激化稱為自旋傳輸(spin transfer)或自旋矩(spin torque)。該現象對於磁記錄之讀寫入速度, 密度, 與元件系統整合將有重大之影響與突破。該研究中我們利用圖案化之磁性多層膜與單層膜來探討電流驅動之磁化反轉行為和磁區壁運動之效應, 多層膜方面將以Co/Ru/Co, Py/Os/Py 為架構並施一垂直於膜面之電流, 來瞭解磁化翻轉之臨界電流密度,並藉由改變非磁金屬之種類瞭解自旋擴散長度(spin diffusion length)對於自旋傳輸過程之影響, 此外藉由改變鐵磁性金屬之種類研究材料自旋極化度(spin polarization)對於自旋傳輸的影響。至於電流驅動磁區壁運動之研究, 則以改變幾何圖案之磁性單層膜為主,目的是藉由形狀異向性來規範反向磁區成核(nucleation)之位置以便於磁區壁運動之觀察。當電流密度之數量級為~107A/cm2 時, 且於某一小於翻轉場(switching)之偏壓場(biasfield)下, 發現因磁區壁運動使得電阻值呈規則性跳動, 電阻產生劇烈變化處之電流稱為臨界電流(critical current)該場稱偏壓場(bias field)

以異向性島狀及圖形化L10 FePt濺鍍薄膜探討磁晶各向異性本質分佈對磁記錄訊號之影響

本研究計畫之目的在探討L10 FePt島狀膜, 顆粒膜及磁性點陣之磁異向場分佈對於磁記錄訊號之影響。由於磁記錄密度的提高, 晶粒度減小且記錄方式由水平式記錄媒體轉變為垂直式記錄媒體, 傳統的磁記錄材料為CoCrBPt (水平記錄) 及CoCrPt/SiO2 (垂直記錄), 熱退火後Cr元素在晶粒邊界處之偏析對於磁記錄媒體之雜訊的消除起了很大之作用, 因此Co原子晶粒間的藕合可以有效的隔絕。 對於下一世代之磁記錄材料目前未明, 使用更高結晶異向性之材料來提高熱穩定性及記錄密度是一方向, 但是如何隔絕晶粒間之藕合目前有許多製程方法, 所得到的就是島狀膜, 顆粒膜及磁性點陣, 這些結構中磁性物質是相互隔絕的, 但是如何得到均一(uniform)的結構是製程上所須考量的, 本研究將利用各種製程參數改變島狀膜, 顆粒膜及磁性點陣之形狀, 並探討不同形狀下, 磁異向場之分佈並藉由磁性的量測及模型之擬合來瞭解異向場分佈所造成之翻轉場分佈及記錄之雜訊。栓固型L10 FePt滲透結構(percolate)垂直記錄媒體之想法在於解決當FePt顆粒小至4nm或更小時之超順磁效應, 由於傳統之水平與垂直記錄媒體均以Cr, SiO2做為晶粒邊界元素來降低晶粒間藕合作用以減少雜訊, 但是當Co晶粒小至某一臨界值其磁矩將不再穩定而進入超順磁態, 因此若能製作出局部性的FePt晶粒是晶粒間藕合的, 而這些顆粒內含數百個晶粒, 更重要的是這些顆粒之表面將披覆著幾奈米之MgO來阻斷顆粒間之藕合效應以降低雜訊, 因此MgO將是一栓固位置(pinning sites)且交互藕合之FePt晶粒將可解決超順磁效應, 此為該研究之目的

磁區壁輔助垂直異向性 Fe/Fe-Pt膜之磁化反轉及磁阻現象探討

Perpendicular magnetic recording with an exchange coupled composite structure seems to be a way to move beyond the so called “trilemma” in recording. Smaller grain size is required for higher recording densities to maintain the numbers of grains per recording element. Higher magnetocrystalline (Ku) materials such as L10 FePt are used to overcome the thermal stability of magnetic media at smaller grain sizes. The high coercivity and switching field of films made from high Ku material must exceed that of the write head field. Exchange-spring (ES) media or exchange coupled composite (ECC) media have demonstrated major advantage over conventional perpendicular media, including a reduction in the switching field for the same thermal stability and greater insensitivity to easy axis distribution. ECC seems to be a method of achieving an area density of several (Tbit/in2).First year, we discuss Fe soft layer thickness and interface roughness on the properties of exchange-spring Fe/FePt bilayer. The influence of Fe soft layer thicknesses on the out-of-plane coercivity (Hc) are discussed by the two spin model for rigid magnetic film. The magnetization reversal of exchange-spring like film was interpreted by domain wall motion. A soft/hard Fe/FePt bilayer with perpendicular magnetization was prepared on a glass substrate. Controlling the Fe layer thickness allowed modification of the hysteresis loops from rigid magnet with perpendicular magnetization to exchange- spring like magnet with parallel magnetization due to the nanoscale soft/hard interface coupling. For rigid magnetic films, the magnetization was reversed at a single switching field and interpreted by the two-spin model. In an exchange-spring like film, the in-plane magnetization reversal process was in two-steps and resulted from domain wall nucleation and propagation from the Fe layer into the FePt layer. Second year, the exchange coupled Fe/FePt bilayer was used in patterned Fe/Pt/MgO/Fe/FePt/glass magnetic tunneling junction. The magnetoresistance and spin transfer torque were discussed.FePt薄膜之L10序化相具有潛力被運用在超高磁記錄密度媒體已被探討多年，該序化合金有下列之優點，具有較高的磁晶各向異性能密度或磁晶各向異性常數Ku (magnetocrystalline anisotropy energy density)，其值約為 4-7x107 erg/cm3，當磁晶各向異性能與熱能(KuV/kBT)之比值約為50~70時其晶粒度足以維持其熱穩定性，因此該序化合金之晶粒熱穩定性(thermal stability grain size)可小至2-3 nm，可有效延遲傳統磁記錄媒體(Co-基合金之穩定晶粒尺寸約為9nm)所面臨之超順磁效應(superparamagnetic effect)。FePt具高磁晶各向異性能, 其矯頑磁力或翻轉場易超過寫頭之寫入場。交互藕合之複合薄膜具有降低翻轉場, 維持熱穩定性且易軸之散亂承受度較高等優點, 因此有機會取代傳統之垂直記錄媒體且達到更高之記錄密度。硬磁與軟磁雙層薄膜, 其界面之交互藕合作用力與界面粗糙度(roughness), 界面擴散(diffusion), 及界面混相(intermixing)生成有很大關聯性。 該研究目的第一年在探討不同硬磁/軟磁界面對於Fe/FePt雙層薄膜磁性之影響。本計畫將以三種製程得出不同之界面特性, 探討其層間之交互藕合作用力。(A)製備平整界面(sharp interface)之SiO2/Fe/FePt雙層膜。平整界面之互藕合作用力與軟磁層厚度相關, 因此其界面交互作用力或矯頑磁力(Hc)隨軟磁層厚度增加而減弱, 當軟磁層厚度小於臨界厚度時, 雙層膜呈現固定磁化之狀態(rigid magnetization), Fe層厚度大於臨界值則磁區壁於軟磁層中生成則呈現兩階段磁化反轉(two-steps magnetization reversal)。該研究目的希望找到軟磁層臨界厚度以及翻轉場(Hsw)隨Fe層厚度變化之趨勢並以雙自旋模型(two-spin model)探討層間交互作用能(Jex)與能量障礙(energy barrier)之變化。(B)製備梯度界面(graded interface)之SiO2/Fe/FePt雙層膜。該研究目的希望了解梯度界面形成對於矯頑磁力, 角形比(squareness ratio)下降之影響, 並配合自旋鏈模型(spin chain model)探討其界面交互作用力。(C)方法(B)對於硬磁/軟磁層界面之調整, 將使矯頑磁力與角形比減小, 方法(C)為製備Fe/Fe-rich FePt/FePt 之三層交互藕合薄膜, 梯度界面區由富Fe之FePt相取代原來之Fe-FePt混相區(intermixing), 因此可維持固定磁化之磁滯曲線且矯頑磁力隨富鐵之FePt層厚度增加而增大。第二年則以將Fe/FePt之交互藕合膜製成 Fe/Pt/MgO/Fe/FePt/glass穿隧磁電阻薄膜之電極層, 其中之穿隧阻障層為MgO, 並製成圖形化元件探討其磁電阻及自旋傳輸矩效應

「雍正王朝」電視劇劇本分析研究

[[abstract]]　　《雍正王朝》電視劇在播出後，除了獲得許多獎項的肯定，也引發了不少的爭議與討論，因此本論文試圖透過相關的戲劇理論，並參考此劇編導的創作理念與劇作家實務的創作經驗來探討此劇的戲劇成就與缺失。　　　本文研究的步驟，其一是掌握雍正王朝內容與演出的研究成果；其二是從雍正形象的轉變與再現來分析雍正皇帝的民間記憶至二月河《雍正皇帝》小說再至《雍正王朝》電視劇中形象的改編意圖；其三是了解此劇中主題的萃取與故事題材的選擇；其四是探討此劇情節的設計要點為何；其五是分析整齣戲劇的結構與布局；其六是分析此劇中人物的選擇方法、刻畫方法與人物類型；最後則提出此劇的戲劇成就與缺失之處，希望能為後來相關的學術研究起到拋磚引玉的作用

Magnetic properties and microstructure of (001) oriented Ag/FePt, Ag/FePt/Ag films

This study fabricates FePt film with (001) preferred orientation on a glass substrate by rapid thermal annealing (RTA) at 800 degrees C for 5 min. The ultrathin Ag capped layer and seed layer were inserted to reduce the ordering temperature. The (001) preferred orientation formed in Ag/FePt bilayer or Ag/FePt/Ag trilayer when annealed at 700 C for 5 min. From transmission electron microscopy (TEM) images, the interface Ag atoms diffused and segregated to form the Ag phase with L1(0) lattice, creating vacancies at the FePt lattice. The phase transformation activation energy was reduced as compared to single layer FePt film. Phase transformation strain dominated during ordering and grain growth. The formation of (001) preferred orientation on glass substrate was achieved by rapid ordering and recrystallization during post annealing. (C) 2009 Elsevier B.V. All rights reserved

Magnetic properties and microstructure of graded Fe/FePt films

A soft/hard Fe/FePt bilayer with perpendicular magnetization was prepared on a glass substrate. Annealed Fe/FePt film allowed modification of the Fe/FePt sharp interface to Fe/(Fe-rich FePt)/FePt graded interface with rigid magnetization due to the nanoscale soft/hard interface coupling. The magnetization was reversed at a single switching field and interpreted by the two-spin model. When the annealed temperature of the Fe/FePt film increased, the remanence magnetization decreased continuously but the out-of-plane coercivity increased obviously at 600-700 degrees C which was interpreted by the graded magnetic anisotropy. The coercivity can be tuning in the exchange coupled composite film. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3446198