Sputter-prepared (001) BiFeO

ABSTRACT: Highly textured BiFeO3(001) films were formed on L10-FePt(001) bottom electrodes on glass substrates by sputtering at reduced temperature of 400 oC. Good electric polarization 2Pr = 80 and 95 muC/cm2, comparable to that of the reported epitaxial films, and coercivity Ec = 415 and 435 kV/cm are achieved in the samples with 20-nm- and 30-nm-thick electrode. The BiFeO3(001) films show different degree of compressive strain. The relation between the variations of strain and 2Pr suggests that the enhancement of 2Pr is resulted from the strain-induced rotation of spontaneous polarization. The presented results open possibilities for the applications based on electric-magnetic interactions.     

斜切基片上溅射生长高密度小尺寸Ge纳米点的研究

采用离子束溅射技术,在斜切的单晶Si基底上生长了高密度的小尺寸Ge纳米点。系统研究了斜切基底上的表面台阶对Ge纳米点生长初期表面原子吸附行为的影响,以及斜切基片上Ge纳米点随原子沉积量的演变规律。实验结果表明,在斜切基片上原子级的表面台阶能有效地抑制吸附原子的表面扩散。因此,有利于Ge纳米点的形核,并抑制纳米点的过度长大,从而获得高密度、小尺寸的Ge纳米点。     

双路8位1GSPS高速模数转换芯片AT184AD001B

T84AD001B是Atmel公司生产的最大采样率可达1Gsps的双通道并行8位高速A／D转换器，在交错模式下使用可以达到2Gsps的采样率。它具有多种模拟输入和时钟输入方式，利用这些特性可实现多功能的数据采集电路方案。介绍了该芯片的主要参数、工作原理和引脚功能，并给出了AT84AD001B与FPGA的接口框图。     

不同暴露比例(001)晶面锐钛矿相TiO2纳米方块的合成及气敏性能

在众多提高TiO_2气敏性能的尝试中,晶面调控的方法引起了极大的关注。主要通过调整水热反应的制备工艺,实现TiO_2的(001)晶面暴露不同比例,对其进行气敏性能的研究。通过改变反应物浓度完成了一系列不同晶面暴露比的TiO_2纳米方块的可控水热合成,实现了对TiO_2纳米方块形貌以及晶面的调控。合成TiO_2纳米方块暴露(001)晶面的比例从33.33%增加到83.33%。随(001)晶面暴露比例的提高,对于丙酮气体的灵敏度从14.3提高到了27.8。     

The influence of DTABr surfactant on the electrokinetic and rheological properties of soda-activated bentonite dispersions

The influence of the cationic surfactant dodecyltrimethylammonium bromide (DTABr) on the electrokinetic and rheological properties of a soda-activated bentonite was investigated. The electrokinetic and rheological measurements of the surfactant-bentonite (2 wt.%) system were performed at three pH values of 4, 8 and 12. The electrokinetic measurement results show that the DTABr was adsorbed on the bentonite mostly at pH 4 and 8, whereas X-ray diffraction (XRD) studies revealed that the DTABr surfactant enters the interlamellar space of the clay mineral at pH 8 and 12. Rheological data showed that the flow behavior changed with the surfactant concentration. The basal d₍₀₀₁₎-spacings of DTABr-treated bentonite samples revealed expandability, from 14.8 to 16.8 Å. XRD results indicate a monolayer arrangement of the DTABr molecules parallel to the silicate layer.     

Study of threading dislocations in the plan-view sample of SiGe/Si(001) superlattices by transmission electron microscopy

Interfacial defects due to a mismatch of 1.378% between substrate and epilayer were examined in a Si_0.67Ge_0.33/Si(001) superlattice by transmission electron microscopy (TEM). Plan-view specimens from the superlattice were prepared to investigate the defects in the structure. It was observed that 60°C-type misfit dislocations associate with point contrast on and at their ends. This point contrast was found to represent threading dislocations by using tilt experiments in the microscope. Consequently, stereo electron microscopy was used to examine the threading dislocations. It was discovered that the threading dislocations are not on the {111} slip planes but can be almost parallel to the [001] zone axis.     

Fe81Ga19合金<001>取向单晶生长及磁致伸缩性能

采用悬浮区熔法,加入籽晶控制生长取向,以4 mm/h的生长速度,制备了轴向〈001〉择优取向的Fe81Ga19单晶.极图测试结果发现,采用偏离轴向〈001〉方向约5°的籽晶生长得到的单晶,生长始端和生长末端轴向取向分别偏离〈001〉取向5°和4°,上下取向差仅为1°.另一单晶采用轴向〈001〉取向籽晶生长得到,当施加6...     

Si(001)面弛豫表面构型与电子结构的第一性原理

采用基于第一性原理的密度泛函方法对Si(001)表面进行理论研究,通过几何优化得到Si(001)表面的稳定结构.在结构优化的基础上,针对该表面研究表面能和原子弛豫与模型中原子层数和真空层厚度的关系.研究结果表明:模型中原子层数和真空层厚度对表面的表面能和原子构型有较大影响.当原子层数为8层,真空层厚度为1 nm时,表面能与原子弛豫程度趋于稳定;与理想晶格相比,表面弛豫导致表面层的电子结构和键合特性发生很大变化.弛豫后,体系能量降为最低,结构趋于更加稳定.     

Effects of Ag Layer on the Structure and Magnetic Properties of FePt:AlN Composite Films

[AlN/FePt] 10 , [AlN/FePt] 10 /Ag and Ag/[AlN/FePt] 10 thin films were deposited by magnetron sputtering onto 7059 glass substrates, then were annealed at 550 °C for 30 min. It is found that introducing non-magnetic Ag underlayer can improve the ordering and (001) preferred orientation of FePt grains. Furthermore, the (001) texture of FePt grains increases with increasing Ag underlayer thickness. However, with Ag top layer given, it can only be observed that the ordering of FePt grains was promoted.