本文關(guān)鍵詞： 磁性多層膜 垂直磁各向異性 隧穿磁電阻 反�；魻栃�(yīng) 自旋軌道矩　出處：《北京科技大學(xué)》2017年博士論文　論文類型：學(xué)位論文

【摘要】：具有納米異質(zhì)結(jié)構(gòu)的磁性薄膜是自旋電子學(xué)的核心應(yīng)用材料。其中,與維度、尺寸密切相關(guān)的表面、界面效應(yīng)又對(duì)材料性能有著至關(guān)重要的影響。本論文著眼于分析鐵磁金屬/氧化物、鐵磁/非磁金屬等異質(zhì)界面對(duì)薄膜材料磁性能以及自旋相關(guān)輸運(yùn)性能的影響;通過(guò)實(shí)驗(yàn)測(cè)量及表征構(gòu)建界面微結(jié)構(gòu)、界面化學(xué)狀態(tài)與材料性能的關(guān)聯(lián);利用界面調(diào)控進(jìn)一步優(yōu)化材料性能;并探索異質(zhì)結(jié)構(gòu)磁性多層膜的新型自旋邏輯應(yīng)用。論文主要研究?jī)?nèi)容及成果如下:(1)成功制備出具有垂直磁各向異性的L10-FePt/MgO/L10-FePt單晶外延隧道結(jié)。將界面結(jié)構(gòu)細(xì)化至原子終止層尺度,結(jié)合理論計(jì)算及界面表征研究了 FePt/MgO界面處不同終止層(Fe或Pt)對(duì)隧穿磁電阻的影響。(2)通過(guò)變溫及偏壓依賴輸運(yùn)測(cè)量研究了 Fe/MgO/Fe/MgO/Fe單晶外延雙勢(shì)壘隧道結(jié)中隨中間Fe層厚度變化的隧穿行為。利用原子分辨的透射電子顯微技術(shù)對(duì)Fe層形貌及界面結(jié)構(gòu)進(jìn)行原位表征,構(gòu)建了動(dòng)態(tài)演變的界面結(jié)構(gòu)與隧穿行為的關(guān)聯(lián),指出MgO/Fe/MgO界面變化會(huì)對(duì)輸運(yùn)通道產(chǎn)生調(diào)制從而影響體系輸運(yùn)性能。(3)聚焦于鐵磁金屬/氧化物界面化學(xué)狀態(tài)對(duì)材料性能的影響,利用化學(xué)穩(wěn)定的氧化物包覆層以及具有強(qiáng)氧親和能力的界面金屬插層,對(duì)無(wú)序FePt薄膜、[Pt/Co]3/MgO多層膜以及Ta/CoFeB/MgO/Ta多層膜三種典型材料體系的磁性能及輸運(yùn)性能進(jìn)行了調(diào)控:采用SiO2包覆無(wú)序FePt超薄膜使其獲得了垂直磁各向異性;在Co/MgO界面處插入優(yōu)化厚度的Ta,[Pt/Co]3/Ta/MgO經(jīng)450℃退火后仍然保持熱穩(wěn)定的垂直磁各向異性和較大的反�；魻栞敵�;將Gd插入CoFeB/MgO界面處,在保持垂直磁各向異性的基礎(chǔ)上Ta/CoFeB/Gd/MgO/Ta的有效阻尼因子較之無(wú)插層時(shí)最多下降70%。(4)基于重金屬/鐵磁金屬/氧化物異質(zhì)結(jié)構(gòu)中自旋軌道矩引起的磁化翻轉(zhuǎn)特性,在具有垂直磁各向異性的Ta/CoFeB/MgO/Ta多層膜中實(shí)驗(yàn)完成了全部16種布爾邏輯運(yùn)算。更進(jìn)一步,結(jié)合電壓調(diào)控界面垂直磁各向異性,仿真設(shè)計(jì)了能夠快速運(yùn)行16種布爾邏輯運(yùn)算的三端自旋邏輯器件單元�；谠撛O(shè)計(jì)思路,實(shí)際器件中通過(guò)優(yōu)化材料結(jié)構(gòu)可以實(shí)現(xiàn)不依賴磁場(chǎng)的邏輯運(yùn)算功能。未來(lái)集成電路中應(yīng)用這種新型的自旋邏輯器件,有望融合非易失存儲(chǔ)和計(jì)算,從而打破當(dāng)前CMOS工藝以及馮·諾依曼架構(gòu)體系所面臨的發(fā)展瓶頸。
[Abstract]:Magnetic thin films with nanoscale heterostructures are the core applications of spin electronics. The interfacial effect has an important effect on the material properties. In this paper, the effects of ferromagnetic metal / oxide, ferromagnetic / non-magnetic metal and other heterogeneous interfaces on the magnetic properties and spin dependent transport properties of thin film materials are analyzed. The interface microstructure was constructed by experimental measurement and characterization, and the relationship between the chemical state of the interface and the properties of the material was obtained, and the properties of the material were further optimized by the interface control. The main contents and results of this thesis are as follows: 1) the epitaxial tunnel junctions of L10-FePt / MgO / L10-FePt single crystal with perpendicular magnetic anisotropy have been successfully fabricated. The interface structure has been refined to the scale of atomic termination layer. Combined with theoretical calculation and interface characterization, the effects of different termination layers (Fe or PT) at FePt/MgO interface on tunneling magnetoresistance were studied. Atomic resolved transmission electron microscopy (TEM) was used to characterize the morphology and interface structure of Fe layer in situ. The relationship between the dynamic evolution of interface structure and tunneling behavior is constructed. It is pointed out that the change of MgO/Fe/MgO interface will modulate the transport channel and thus affect the transport performance of the system. Using chemically stable oxide coating and interfacial metal intercalation with strong oxygen affinity, The magnetic properties and transport properties of disordered FePt films, [Pt/Co] 3 / MgO multilayers and Ta/CoFeB/MgO/Ta multilayers were regulated. The perpendicular magnetic anisotropy was obtained by using SiO2 coating disorder FePt ultrathin films. At the Co/MgO interface, the optimized thickness Ta, [Pt/Co] 3 / Ta / MgO remains thermally stable perpendicular magnetic anisotropy and large anomalous Hall output after annealing at 450 鈩，

本文編號(hào)：1542009