五磷酸钕晶体中铁弹畴界的X射线形貌研究

利用X射线衍射形貌法,研究了五磷酸钕(NdP₅O₁₄)晶体中铁弹畴界的衍射衬度。发现在μt=0.6—7范围内,畴界呈现黑的或白的衬度。畴界衍射衬度的特征可归结为(c₂-c₁=)△c∥g畴界衬度明显△c⊥g畴界衬度消失△c·g>0畴界呈黑衬度△c·g<0畴界呈白衬度利用Penuing-Polder波点迁移原理,对畴界的衬度形成原理做了定性解释。根据畴界的衍射衬度特征,定性讨论了畴界的结构特征。 关键词：     

n-GaAs表面全息光栅的形成及表面等离振子电磁耦子发光测定

本文讨论n-GaAs表面采用H₂O₂-H₂SO₄系光加速腐蚀形成衍射光栅的方法,以及Ag/n-GaAs肖脱基势垒二极管表面等离振子电磁耦子发光的测定。 关键词：     

Fe-Si-Al合金的中子衍射研究

用中子衍射方法测定了Fe-Si-Al合金的长程有序度和Fe原子的磁矩。结果表明,合金经不同冷却速度的热处理后,其长程有序度是不同的,这种有序度的差异可能是造成二者有显著不同的磁导率的重要原因之一。 关键词：     

KTP(001)晶体分光性能研究

根据同步辐射光源对软X射线分光晶体的性能要求,分析了软X射线能区常用分光晶体的性能优劣,指出对于晶格常数值大的分光晶体,KTP(KTiOPO₄)(011)是该能区比较理想的分光晶体. 同时提出了一种利用同步辐射光源测量晶体衍射效率的实验方法,指出光源的发散度与晶体的衍射效率密切相关. 测量了KTP(011)晶体的晶格常数,给出了KTP(011)晶体的实测衍射效率. 关键词： 同步辐射 KTP(011)晶体 衍射效率 光源发散度     

双重复合式液晶/聚合物电调谐光栅的制备

采用一次性全息曝光的方法同时在样品上制备了周期分别为1μm和4μm,衍射效率电场可调的双重复合式液晶/聚合物光栅.使用He-Ne激光器对复合光栅的衍射特性进行了实验研究,发现光栅存在两个1级衍射极强峰.对峰值衍射效率的测定结果表明,周期1μm的光栅衍射效率为90%,周期4μm的光栅,60%.结合耦合波理论计算了周期1μm和4μm光栅的衍射效率理论值,分别为92.57%和63.68%.实验结果与理论值符合得非常好.对电光特性的测试表明该复合光栅内的两套子光栅的驱动电压V₉₀关键词： 光栅 液晶     

乙酰苦玄参甙元(Ⅰ)的晶体结构测定

苦玄参甙元(I)为植物苦玄参的有效成分之一。乙酰苦玄参甙元(I)(k×k)为其乙酰化合物,分子式为C₃₄H₄₈O₇,属正交晶系,空间群为D₂⁴-P2₁ 2₁ 2₁,晶胞参数为a=22.357(10)?,b=15.277(8)?,c=9.089(4)?。晶胞内分子数z=4。用PW-1100四圆衍射仪收集衍射强度数据,独立衍射点为2234个。用直接法(MULTAN-78)测定晶体结构。结构参数的修正采用全矩阵最小二乘法,R=0.1099,由差值Fourier综合得到氢原子位置。 关键词：     

N-(3,4-次甲二氧桂皮酰基)-哌啶的晶体结构测定

一种临床使用的抗癫痫药物——N-(3,4-次甲二氧桂皮酰基)-哌啶的晶体结构已被测定,化学式为C₁₅H₁₇O₃N₁,属正交晶系,空间群为D₂⁴-P2₁ 2₁ 2₁,晶胞参数α=24.338(4)?,b=8.558(2)?,c=6.217(2)?,晶胞内分子数z=4,用PW-1100四圆衍射仪收集衍射强度数据,以 关键词：     

K0.5Bi0.5TiO3—Na0.5Bi0.5TiO3系统铁电陶瓷相界的X射线研究

用X射线衍射方法测定了K_0.5Bi_0.5TiO₃—Na_0.5Bi_0.5TiO₃系统不同组分试样的点阵常数和相变温度,确定了四方-三方相界组成。给出了K_0.5Bi_0.5TiO₃和Na_0.5Bi_0.5TiO₃的多晶X射线衍射数据。 关键词：     

掺铥钨酸钡单晶生长和光谱研究

采用Czochralski 法生长出光学质量的BaWO₄:Tm³⁺单晶,利用X粉末衍射实验确定了不同掺杂浓度晶体的晶胞参数.测定了晶体的室温吸收光谱,应用Juud-Ofelt理论,拟合了光谱的3个强度参数,其值分别为Ω₂=404×10^-20cm²,Ω₄=0509×10^-20cm²,Ω关键词： 4：Tm³⁺单晶')" href="#">BaWO₄：Tm³⁺单晶 吸收谱 光谱参数 上转换发光     

邻苯二甲酸氢钾(KAP)单晶中包裹物的X射线衍射形貌衬度

本文描述邻苯二甲酸氢钾(KAP)单晶中包裹物的X射线衍射形貌衬度及其本质的测定结果。提出应用“包裹物点缀”形貌技术测定单晶中大面积应变区本质的实验方法和结果,为深入了解晶体结构内部薄弱环节提供另一可行的途径。 关键词：     

CdTe太阳电池前电极SnO2:F/SnO2复合薄膜性能分析

减薄CdS窗口层是提高CdS/CdTe太阳电池转换效率的有效途径之一,减薄窗口层会对器件造成不利的影响,因此在减薄了的窗口层与前电极之间引入过渡层非常必要.利用反应磁控溅射法在前电极SnO₂:F薄膜衬底上制备未掺杂的SnO₂薄膜形成过渡层,并将其在N₂/O₂=4 ∶1,550 ℃环境进行了30 min热处理,利用原子力显微镜、X射线衍射仪、紫外分光光度计对复合薄膜热处理前后的形貌、结构、光学性能进行了表征,同时分析了复     

包钴型r-Fe2O3磁粉各向异性研究

包钴型γ-Fe₂O₃磁粉的矫顽力可比原γ-Fe₂O₃磁粉提高8000—32000A/m。木文研究探讨了两种包钴型γ-Fe₂O₃磁粉(包钴γ-Fe₂O₃和包钴包亚铁γ-Fe₂O₃)的单轴各向异性的起源和矫顽力增大的机制。包钴γ-Fe₂O₃磁粉矫顽力 关键词：     

∑关系线性理论的应用(Ⅰ)——∑4关系在晶体结构测定中的应用

本文系统论述实现Σ₄关系计算的具体方法及其实际应用价值。对五个不同类型的已知晶体结构计算表明,利用Σ₄关系能够获得大量的、可靠性较高的O,π型结构半不变量相角。文中讨论了它们在测定晶体结构中的可能应用前景。 关键词：     

Investigations of the magnetic structure of the surface and volume of aluminum-substituted Sr-M type hexaferrites

The magnetic structure of the surface layer of single crystals of hexagonal ferrites of the type Sr-M (SrFe₁₂O₁₉) in which some iron ions are replaced by diamagnetic Al ions is investigated, in direct comparison with the magnetic structure in the bulk of the sample, by the method of simultaneous gamma, x-ray, and electron Mössbauer spectroscopy. It is found that under conditions of diamagnetic dilution of the magnetic lattice of hexagonal ferrites of the type Sr-M by Al ions, a layer ~200 nm thick in which the orientation of the magnetic moments is not collinear with the direction of the moments in the bulk of the sample is observed on the surface of SrFe_10.2Al_1.8O₁₉ crystals. Thus a “transitional” surface layer has been observed on macroscopic ferromagnetic crystals.     

Effects of Cr underlayer and Pt buffer layer on the interfacial structure and magnetic characteristics of sputtered FePt films

This work develops a new method for growing L1₀ FePt(0 0 1) thin film on a Pt/Cr bilayer using an amorphous glass substrate. Semi-coherent epitaxial growth was initiated from the Cr(0 0 2) underlayer, continued through the Pt(0 0 1) buffer layer, and extended into the L1₀ FePt(0 0 1) magnetic layer. The squareness of the L1₀ FePt film in the presence of both a Cr underlayer and a Pt buffer layer was close to unity as the magnetic field was applied perpendicular to the film plane. The single L1₀ FePt(1 1 1) orientation was observed in the absence of a Cr underlayer. When a Cr underlayer is inserted, the preferred orientation switched from L1₀ FePt(1 1 1) to L1₀ FePt(0 0 1) and the magnetic film exhibited perpendicular magnetic anisotropy. However, in the absence of an Pt intermediate layer, the Cr atoms diffused directly into the FePt magnetic layer and prevented the formation of the L1₀ FePt(0 0 1) preferred orientation. When a Pt buffer layer was introduced between the FePt and Cr underlayer, the L1₀ FePt(0 0 1) peak appeared. The thickness of the Pt buffer layer also substantially affected the magnetic properties and atomic arrangement at the FePt/Pt and Pt/Cr interfaces.     

Ultrathin (CoFe/Pt)n multilayers with tuned magnetic properties

Perpendicular magnetic anisotropy (PMA) has been investigated in ultrathin (CoFe [0.2] nm/Pt [0.2] nm)_n multilayers. The Pt layers show an fcc crystal structure with a preferred [111] orientation. The multilayers with n=3, 4 show PMA in the as-grown state, which can be enhanced by thermal annealing. However, no PMA is observed in the as-grown state with higher repetitions (n>&=5), although it is observed after thermal annealing. For 1=&<n=&<8, the anisotropy energy is around 10⁵ J/m³ for all (CoFe [0.2]/Pt [0.2])_n stacks. The perpendicular anisotropy is related to layer thickness and interface roughness.     

激光干涉结晶技术制备二维有序分布纳米硅阵列

利用结合移相光栅掩模 (PSGM) 的激光结晶技术在超薄a-SiN_x/a-Si:H/ a-SiN _x三明治结构样品中制备出二维有序分布的纳米硅阵列.原始样品是用等离子体 增强化学气相淀积法生长.a-Si:H层厚为10nm，a-SiN_x 为50nm，衬底材料为SiO ₂/Si或 熔凝石英.原子力显微镜、剖面透射电子显微镜、高分辨透射电子显微镜对样品表面形貌和 微结构的观测结果表明，采用该方法可以在原始淀积的a-Si:H层中得到位置可控的晶化区域 ：每个晶化区域直径约250nm，具有同PSGM一致的2μm周期；晶化区域内形成的纳米硅 颗粒尺寸接近原始淀积的a-Si:H层厚，且晶粒的择优取向为<111>. 关键词： 纳米硅 激光结晶 定域晶化 移相光栅     

The effects of Si3N4 interlayer on the thermal stability and hardness of Ti/TiNx (x = 0.5-1) nanolayered coatings

The polycrystalline Ti/TiN_x multilayer films were deposited by magnetron sputtering, and the as-deposited multilayer coatings were annealed at 500-800 °C for 2-4 h in vacuum. We investigated the effects of annealing temperature and annealing time on the microstructural, interfacial, and mechanical properties of the polycrystalline Ti/TiN_x multilayer films. It was found that the hardness increased with annealing temperature. This hardness enhancement was probably caused by the preferred crystalline orientation TiN(1 1 1). The X-ray reflectivity measurements showed that the layer structure of the coatings could be maintained after annealing at 500 °C and the addition of the Si₃N₄ interlayer to Ti/TiN_x multilayer could improve the thermal stability to 800 °C.     

Microstructure and discharge properties of Mg-Zr-O protective films in plasma display panel

Mg-Zr-O protective films for plasma display panels (PDPs) were deposited on soda-lime glass substrates by magnetron sputtering method. The effects of Zr doping on both the discharge properties (firing voltage, V_f and the minimum sustaining voltage, V_s) and the microstructure of the Mg-Zr-O films were investigated. The results show that the deposited Mg-Zr-O films retain the NaCl-type structure as the pure MgO crystal. The doped Zr exists in the form of Zr⁴⁺ substitution solution in MgO crystal and an appropriate amount of Zr can improve the surface characteristics of the Mg-Zr-O films effectively. When the Zr atomic concentration is about 2%, the Mg-Zr-O films have the strongest (2 0 0) preferred orientation and the minimum surface roughness. The firing voltage and the minimum sustaining voltage of Mg-Zr-O protective layer are reduced at most by about 25 V and 15 V, respectively, compared with those of the pure MgO film. Mg-Zr-O protective layers with an appropriate amount of Zr are promising to meet the demands of advanced high-vision PDPs.     

Hyperfine field distribution in electrodeposited iron-nickel alloys

The distribution of hyperfine fields in f.c.c. electrodeposited iron-nickel alloys with composition ranging from 10 to 27 at% Fe has been studied from the observed Mössbauer spectra using a method of analysis developed by Hesse and Rübartsch. The different I_2,5/I_1,6 values for the different parts of the same component sample indicate that the distribution of the electrical field in bath plays an important role in the spin preferred orientation within electrodeposited layer. The asymmetry in the width of Mössbauer lines has been discussed.