PZT薄膜的相转变与晶格参数的研究

研究Ｓｏｌ－ｇｅｌ制备ＰＺＴ薄膜材料相结构与晶格参数,研究ＰＺＴ薄膜相变、衬底与温度关系和不同Ｚｒ／Ｔｉ比Ｐｂ（ＺｒｘＴｉ１－ｘ）Ｏ３（ｘ＝０．２～０．８）。结果表明：ＰＺＴ薄膜从烧绿石相向钙钛矿相转变的温度在Ｐｔ衬底上为６００℃,在不锈钢上为６５０℃。ＰＺＴ铁电体薄膜的晶格参数和晶格畸变随Ｚｒ／Ｔｉ比的不同而变化;在铁电四方相区,随Ｚｒ含量增加,ａ＝ｂ轴逐渐增大,ｃ轴稍有缩短,四方晶系发生畸变;     

PZT铁电薄膜的射频磁控溅射制备及其性能

实验采用射频磁控溅射工艺,在较低的衬底温度(370℃)、纯Ar气氛中和在(111)Pt/Ti/S iO2/S i衬底上用陶瓷靶Pb(Zr0.52Ti0.48)O3(PZT)制备具有完全钙钛矿结构的多晶PZT(52/48)铁电薄膜,沉积过程中基片架作15°摇摆以提高膜厚的均匀性,然后在大气环境中对沉积的PZT薄膜进行快速热退火处理。用电感耦合等离子体原子发射光谱(ICP-AES)和Auger电子能谱(AES)测量其组分,X射线衍射仪(XRD)分析PZT薄膜的相结构和结晶取向,RT66A标准铁电测试系统分析Pt/PZT/Pt/Ti/S iO2/S i电容器的电学特性。结果表明:PZT铁电薄膜具有较高的剩余极化(Pr=44.9μC/cm2)和低的漏电流(10-8A量级)。     

在LiNaO3基底上制备PZT铁电薄膜及其电性能研究

采用溶胶-凝胶法在LaNiO3/Si衬底上制作Pb(Zr0.5,Ti0.5)O3(PZT)薄膜,研究了退火温度对薄膜结构和性能影响.通过X-ray分析表明,在600℃退火时,PZT薄膜已形成钙钛矿相,且在(100)择优取向的LaNiO3底电极上制备得到了(100)择优取向的PZT薄膜.实验测得以LaNiO3为衬底上的PZT薄膜的剩余极化强度为Pr=26.83μC/cm2,矫顽场Ec=30.43 kV/cm,介电常数为ε=5509,介电损耗为0.203.     

不同衬底对溅射Pb(Zr_(0.8)Ti_(0.20))O_3薄膜的结构及其性能的影响

利用射频磁控溅射法在低阻Si,Si O2/Si以及Pt/Ti/Si O2/Si等不同衬底上制备了Pb(Zr0.8Ti0.2)O3薄膜.利用XRD,SEM等对薄膜的结构性能进行了分析,结果发现不同衬底对溅射制备的PZT薄膜的结构有很大影响.在Pt/Ti/Si O2/Si衬底上制备的PZT薄膜经600℃退火1h后,薄膜表面光滑、无裂纹,XRD分析显示PZT薄膜呈完全钙钛矿结构,测试PZT薄膜的电学性能,表明PZT薄膜具有良好的介电性能.     

PZT薄膜的结晶特性及红外特性

采用电子柬蒸发方法在n—Si（100）衬底上制备Pb（ZrxTi1-x）O3（简记为PZT）多晶薄膜．用X射线衍射分析了PZT薄膜的结晶择优取向与Zr／Ti成分比、生长温度、退火气氛和退火温度的关系．结果表明不同Zr／Ti比的薄膜在真空中退火都形成（110）择优取向;而在空气中退火后薄膜的择优方向与Zr／Ti成分比有关,Zr／Ti比值小时为（101）择优取向,Zr／Ti大时为（100）择优取向．红外吸收光谱的测量结果表明（100）和（110）择优取向的PZT薄膜在长红外波段（8～12um）存在较强的吸收峰,而（101）择优取向的PZT薄膜在这一波段没有明显的吸收峰．     

脉冲激光沉积法制备的Pb(Zr0.4Ti0.6)O3铁电薄膜漏电机理

利用准分子脉冲激光器在Pt/Ti/SiO2/Si(111)衬底上制备了Pb(Zr0.4Ti0.6)O3(PZT)铁电薄膜.利用掩膜技术,采用磁控溅射法在PZT薄膜上生长Pt上电极,构架了Pt/PZT/Pt铁电电容器异质结.采用X射线衍射和电容耦合测试技术分别表征了PZT铁电薄膜的微结构和电学性能.研究发现:在5 V的测试电压下,在560℃较低的沉积温度下生长的PZT薄膜电容器的剩余极化强度为187 C/m2、矫顽电压为2.0 V、漏电流密度为2.5×10-5A/cm2.应用数学拟合的方法研究了Pt/PZT/Pt的漏电机理,发现当电压小于1.22 V时,Pt/PZT/Pt电容器对应欧姆导电机理;当电压大于2.30 V时,对应非线性的界面肖特基传导(Schottky emission)机理.     

PZT薄膜的制备及特性

用电子束蒸发法在n-Si（100）衬底上制备了Pb（Zr0．52Ti0．48）03（PZT）多晶薄膜,研究了薄膜的表面形貌、结晶特性、红外吸收特性随生长温度和退火温度的变化关系,发现较高的生长温度有利于（101）方向晶粒的择优生长,较高的退火温度能促进（101）方向的晶粒向（110）方向的晶粒转变,（110）择优方向的薄膜对长红外波段的吸收比（101）择优方向的薄膜明显增强．     

不同m(Zr)/m(Ti)及靶形式在不同衬底上溅射PZT薄膜的研究

分别用m(Zr)/m(Ti)配比为30/70、53/47、70/30的源材料及陶瓷块状靶和预烧粉末靶的形式,在Ag、Au、Pt衬底上溅射制取PZT薄膜.比较分析了薄膜的钙钛矿结构形成情况,所需的热处理温度及铁电特性.研究表明:靶材的配比靠近30/70时较容易获得钙钛矿结构;用预烧粉末靶或用Ag衬底可降低热处理温度;用Au、Pt衬底能得到较好的电学特性.     

磁控溅射参数对钛酸锶钡薄膜生长及介电性能的影响

在Pt/Ti/SiO2/Si(110)衬底上利用射频磁控溅射法制备了Ba1-xSrxTiO3(BST)薄膜.基于薄膜的形核理论,研究了成膜时间、衬底温度、溅射功率、溅射气压、氧氩比、退火热处理等参数对薄膜的表面形貌和介电性能的影响.结果表明:在其他溅射参数一定的条件下,薄膜的厚度随溅射时间成指数关系增长;在退火温度600℃下热处理20min薄膜完全晶化;调节衬底温度、溅射功率、溅射气压等参数有助于制备出表面致密、晶粒大小均匀、具有高介电常数和低损耗的BST薄膜.     

Sol-Gel法在不同衬底上制备的LaNiO_3导电薄膜的性能研究

采用溶胶凝胶法快速成膜工艺分别在Si(100),SiO2/Si,Pt/Ti/SiO2/Si不同基底上制备LaNiO3导电薄膜,并分别以LNO和Pt/Ti为基底制备PZT薄膜。通过XRD,AFM,EDS等测试手段对LNO导电薄膜的结构及组成进行表征,并通过XRD,介电性能的测试比较LNO/Si和Pt/Ti沉积PZT薄膜的性能。结果表明,在Si(100),Pt/Ti/SiO2/Si上制备的LaNiO3导电薄膜是赝立方结构,而在SiO2/Si衬底上是四方结构。在Si(100)上得到的LNO薄膜致密、平整,可以作为制备PZT薄膜的导电层。在LNO和Pt/Ti上制备的PZT薄膜均为钙钛矿结构,且PZT/LNO薄膜各衍射峰强度优于PZT/Pt/Ti;而介电性能方面,PZT/LNO较PZT/Pt/Ti稍差,100kHz时,PZT/LNO和PZT/Pt/Ti的介电常数和介电损耗分别为562,0.29;408,0.037。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the