發(fā)布時(shí)間：2018-02-14 12:19

  本文關(guān)鍵詞： 磁性薄膜 反�；魻栃�(yīng) 垂直磁各向異性 熱穩(wěn)定性　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】：自旋電子學(xué)是研究電子自旋相關(guān)輸運(yùn)過程及相應(yīng)器件的一門新興交叉學(xué)科,基于電子的電荷與自旋屬性發(fā)展起來的自旋電子器件廣泛應(yīng)用在量子計(jì)算機(jī)、納米邏輯器件、磁存儲(chǔ)、衛(wèi)星、個(gè)人電腦等先進(jìn)領(lǐng)域。新型的自旋電子器件與傳統(tǒng)的電子器件相比具有非易失性、高集成度、處理速度快、能耗低等顯著優(yōu)勢(shì),能夠更好的滿足未來電子器件微型化、集成化、智能化的需求。因此優(yōu)化設(shè)計(jì)具備高性能的自旋電子材料就顯得尤為重要。目前自旋電子材料廣泛實(shí)用化還面臨著一些問題：(1)作為存儲(chǔ)器件的磁性薄膜材料要有良好的垂直磁各向異性；(2)輸出信號(hào)要大：(3)同時(shí)做成器件時(shí)要與后續(xù)的半導(dǎo)體結(jié)構(gòu)和工藝技術(shù)相兼容,材料需要經(jīng)過350℃的退火處理過程,因此還要具有較好的熱穩(wěn)定性。本論文的研究工作就圍繞這三個(gè)問題展開。由于之前研究者的工作主要是從界面的原子尺度和幾何角度出發(fā),如薄膜厚度以及界面的匹配程度、應(yīng)力、缺陷、粗糙度、擴(kuò)散等方面對(duì)磁性能及輸運(yùn)性能進(jìn)行了研究,而更微觀的界面狀態(tài)的影響其實(shí)更為重要,需深入研究。因此,本論文通過引入催化劑、金屬插層及氧化物覆蓋層等手段制備了不同系列的多層膜材料,研究了界面狀態(tài)對(duì)磁性及輸運(yùn)性能的影響,通過調(diào)控界面狀態(tài)優(yōu)化了多層膜的性能。豐要研究?jī)?nèi)容及成果如下：研究了過渡金屬Ru的催化能力對(duì)MgO/CoFeB/Ta/MgO多層膜垂直磁各向異性的調(diào)控作用。我們發(fā)現(xiàn)催化劑Ru較強(qiáng)的氧儲(chǔ)存／釋放能力可以調(diào)控界面氧遷移使界面處原子獲得適度的氧化,從而在無需退火制備態(tài)下就可以成功誘導(dǎo)MgO/CoFeB/Ta/MgO多層膜呈現(xiàn)良好的垂直磁各向異性。該研究成功利用催化劑促進(jìn)了界面氧遷移,為調(diào)控自旋電子材料垂直磁各向異性提供了一種新的方法。研究了重金屬元素Ru和輕金屬元素Mg插入CoFeB多層膜體系后界面電子散射作用及其對(duì)反�；魻栃�(yīng)的影響。結(jié)果發(fā)現(xiàn),引入Mg后形成的MgO納米顆粒彌散在界面處增加了雜質(zhì)散射中心,對(duì)傳導(dǎo)電子具有較強(qiáng)的漫散射作用,從而能夠顯著提高反�；魻栯娮杪�,而Ru引入后形成的金屬／金屬界面產(chǎn)生的散射中心較少,漫反射作用較弱,加之金屬的分流作用反而較低了反�；魻栯娮杪�。研究了Fe／氧化物界面化學(xué)狀態(tài)對(duì)于[Pt/Fe]_3多層膜反�；魻栞斶\(yùn)性能的影響。我們發(fā)現(xiàn)在[Pt/Fe]_3氧化物覆蓋層的異質(zhì)結(jié)構(gòu)中,Fe／氧化物界面的化學(xué)狀態(tài)的變化對(duì)反�；魻栯娮杪示哂兄匾绊�。當(dāng)[Pt/Fe]_3多層膜上層覆蓋MgO時(shí),退火前反�；魻栯娮杪首兓�350%,而上層覆蓋物為SiO_2時(shí),反�；魻栯婈幝蕛汉鯖]有變化。通過XPS發(fā)現(xiàn),MgO的引入使[Pt/Fe]_3多層膜的Fe/MgO界面處原子化學(xué)狀態(tài)發(fā)生了明顯的改變,從而導(dǎo)致了飽和磁化強(qiáng)度增大,這是其反�；魻栃�(yīng)增強(qiáng)的豐要原因。研究了HfO_2覆蓋層和Pt插層對(duì)Co/Ni多層膜垂直磁各向異性退火穩(wěn)定性及其反常霉?fàn)栞斶\(yùn)性能的影響。實(shí)驗(yàn)發(fā)現(xiàn),引入HfO_2覆蓋層后,Co/Ni多層膜的垂直磁各向異性的退火穩(wěn)定性提高到了400℃,反�；魻栯娮杪试�375°時(shí)最高達(dá)到0.85μΩ·cm,與制備態(tài)相比提高了211%。同時(shí)發(fā)現(xiàn)隨著Pt插層厚度的增加,有效磁各向異性能Keff隨之增加。說明HfO_2覆蓋層和Pt插層都能有效的提高Co/Ni體系的垂直磁各向異性性能。
[Abstract]:Spintronics is a new interdisciplinary research on electron spin transport process and corresponding devices, spin electronic devices developed in the electronic charge and spin properties based on extensive application in quantum computer, nanometer logic devices, magnetic storage, satellite, personal computer and other advanced fields. Electronic devices spin electronic devices with the traditional model compared with a non-volatile, high integration, fast processing speed, low power consumption advantages, can better meet the future miniaturization of electronic devices, integrated, intelligent demand. So the optimal design with high performance spintronic materials is particularly important. At present, the application of spintronic materials is also facing some question: (1) as the magnetic thin film memory device has good perpendicular magnetic anisotropy; (2) output signal to: (3) at the same time to do nothing and after The semiconductor structure and technology compatible materials need to be continued, after annealing process of 350 DEG C, and therefore also has good thermal stability. The research work of this thesis will focus on these three issues. Because of the researcher's work mainly from the perspective of the interface of the atomic scale and geometry, such as matching degree, thin film the thickness and interfacial stress, defects, roughness, diffusion and other aspects of the study on magnetic properties and transport properties, and the effect of the interface state of the micro is more important, need further study. Therefore, this paper through the introduction of catalyst, multilayer materials of different series of prepared metal intercalation and oxide coatings and other means, the interface of state transport properties of magnetic and, through the regulation of interface state to optimize the performance of multilayer film. The main research contents and results are as follows: Research on the transition of gold Regulation of Ru on the catalytic ability of MgO/CoFeB/Ta/MgO multilayer films with perpendicular magnetic anisotropy. We found that the catalyst Ru strong oxygen storage / release capacity can control the interface at the interface of atomic oxygen transfer to moderate oxidation, which is induced by power MgO/CoFeB/Ta/MgO multilayers exhibiting perpendicular magnetic anisotropy can be good without annealing preparation state. This study successfully used catalyst interface oxygen migration promoted, provides a new method for the manipulation of spin electronic materials perpendicular magnetic anisotropy. The effects of heavy metal elements Ru and light metal element Mg is inserted into the CoFeB multilayer system interface electron scattering and its effect on the anomalous Holzer effect. The results showed that MgO the nano particle dispersion is formed after the introduction of Mg increased the impurity scattering centers at the interface, has a strong role in the diffuse scattering of conduction electrons, which significantly To improve the anomalous Holzer resistivity, metal / metal interface and after the introduction of Ru to produce scattering center less diffuse reflection effect is weak, and the shunt metal has relatively low resistivity anomalous Holzer. Study on the chemical state of Fe / oxide interface transport properties for [Pt/Fe]_3 films. We found that the anomalous heterogeneous structure in Holzer [Pt/Fe]_3 oxide covering layer, changes in the chemical state of Fe / oxide interface has an important influence on Holzer. When the abnormal resistivity of [Pt/Fe]_3 multilayer upper cover MgO, annealing before the anomalous Holzer resistivity change 350%, while the upper cover is SiO_2, Holzer anomalous resistivity almost no change. Discovered by XPS the introduction of MgO, the Fe/MgO atom at the interface chemical state of [Pt/Fe]_3 multilayers changed significantly, which leads to the increase of saturation magnetization, which is abnormal The Holzer effect enhanced the main reason. On the HfO_2 layer and the Pt intercalation of Co/Ni multilayers with perpendicular anisotropy, annealing stability and abnormal mold transport performance. The experimental results showed that, the introduction of HfO_2 coating after annealing stable perpendicular magnetic anisotropy of Co/Ni multilayer film is increased to 400 DEG C, Holzer in 375 degrees when abnormal resistivity reaches 0.85 mu. Cm, and preparation of state higher than 211%. also found that with the increase of the Pt thickness, the effective magnetic anisotropy of Keff increased. HfO_2 layer and Pt layer are perpendicular magnetic anisotropy properties effectively improve Co/ Ni system.

【學(xué)位授予單位】：北京科技大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB383.2

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本文編號(hào)：1510692