C60单晶的汽相生长

报道使用Ｃ₆₀粉末，利用双炉装置，通过闭管汽相法生长Ｃ₆₀单晶的实验及结果。Ｃ₆₀单晶的质量很好，较大单晶的尺寸为０．５ｍｍ×０．６１ｍｍ×１．０ｍｍ。Ｘ射线衍射和电子衍射图的分析得到室温下Ｃ₆₀单晶为ｆｃｃ结构，确定了晶格常数，还进行了Ｒａｍａｎ光谱实验，实验结果表明，热、冷区温度及两者的温度差是影响大尺寸Ｃ₆₀单晶汽相生长的主要因素，对此进行了详细的讨论。 关键词：     

纳米软磁合金的双相无规磁各向异性模型

按照Ａｌｂｅｎ非晶无规磁各向异性的处理方法，考虑纳米软磁合金的双相组织结构的特点，提出了双相无规磁各向异性模型，得到了纳米软磁合金的有效磁各向异性与显微结构参数及铁磁相磁特性参数间的关系，探讨了磁性与有效磁各向异性的关系．用Ｆｅ_７３.５Ｃｕ_１.０Ｎｂ_３.０Ｓｉ_１３.５Ｂ_９.０纳米软磁合金的Ｘ射线衍射结构分析及磁测量结果进行了分析及验证，为上述研究提供了有力的支持 关键词：     

LaxBi2-xTi4O11的合成及相变研究

合成了Ｌａ_xＢｉ_2-xＴｉ₄Ｏ₁₁系列样品，并完成了它们的喇曼光谱和ｘ射线衍射测量；结果表明，该体系在Ｘ＝１．２经历了一次相变，且相变与最低频声子模随Ｘ的变化有关。Ｌａ_0.2Ｂｉ_1.8·Ｔｉ₄Ｏ₁₁的相变温度为２００℃。初步获得Ｌａ₂Ｔｉ₄Ｏ₁₁的结构为正交结构。 关键词：     

金属有机化学气相沉积法制备钛酸铅铁电薄膜

利用低压ＭＯＣＶＤ工艺分别在（００１）取向的ＬａＡｌＯ_３，ＳｒＴｉＯ_３和重掺杂硅单晶衬底上制备ＰｂＴｉＯ_３铁电薄膜，并通过Ｘ射线衍射谱对薄膜的微结构进行分析．Ｘ射线θ－２θ扫描显示硅衬底上得到了ＰｂＴｉＯ_３多晶薄膜，另两种衬底上得到了择优取向的ＰｂＴｉＯ_３薄膜．ＬａＡｌＯ_３衬底上的ＰｂＴｉＯ_３薄膜有ａ和ｃ两个取向，也就是薄膜中存在着９０°畴结构，而生长在ＳｒＴｉＯ_３衬底上的ＰｂＴｉＯ_３薄膜中只存在ｃ方向的择优取向．由于薄膜的尺度效应，发现ｃ轴晶格常数与块材相比均缩短．Ｘ射线的φ扫描验证了后两类薄膜的外延特性，利用同步辐射的高强度和高能量分辨率用摇摆曲线方法研究了这两种外延薄膜的品质，进一步证明了ＳｒＴｉＯ_３衬底上的ＰｂＴｉＯ_３薄膜的单畴特性．利用重掺杂的硅衬底作底电极，测量显示直接生长于硅衬底上的ＰｂＴｉＯ_３多晶薄膜具有良好的铁电性能 关键词：     

块体非晶合金Zr55Cu30Al10Ni5 结构弛豫的研究

应用同步辐射小角x射线散射和差示扫描量热分析对块体非晶合金Zr55₅₅Cu 30₃₀Al10₁₀Ni5₅结构弛豫进行了研究.实验结果表 明：经340℃、不同时间退火后的非晶内 部的电子密度涨落随退火时间的延长先增大而后减小；玻璃转变温度附近焓弛豫峰的表观激 活能则随退火时间的延长先减小而后增大.结果反映了随退火时间的延长，块体非晶合金内 部类液体区不断减少及类固体区不断增加的过程. 关键词： 小角x射线散射 块体非晶合金 结构弛豫     

高聚物(PEO)n-CuBr2薄膜在流体静高压下的离子导电性

用混溶蒸发法制备出高聚物（ＰＥＯ）_n－ＣｕＢｒ₂（ｎ＝４，８，１２，１６，２４）薄膜。并详细测量它们在０．１－３５０ＭＰａ静水压范围的复阻抗谱，以及在０．１－２４００ＭＰａ静水压范围的交流电导率。结果表明：离子电导率与压力的依赖关系可分解为四段相迭加的线性关系。根据Ｘ射线衍射物相分析，它们分别归于ＰＥＯ非晶相的压力效应，ＰＥＯ结晶相的压力效应和析出新相ＣｕＢｒ₂的压力效应。最后给出克服办法——添加少量增塑剂碳酸乙烯酯可增加（ＰＥＯ）_n－ＣｕＢｒ₂薄膜的弹性，使压力下的离子电导率提高一至两个数量级。 关键词：     

回火金属玻璃小角X射线散射强度的背底校正

提出校正回火金属玻璃（非晶合金）小角ｘ射线散射强度的背底误差的方法：将淬火态非晶合金的小角Ｘ射线散射强度作为在相同的实验条件下得到的回火非晶合金小角Ｘ射线散射强度的背底而予以扣除。并将这样扣除背底和用通常方法扣除背底得到的结果相比较，由前者得到的散射强度遵从Ｐｏｒｏｄ律，并进而得到Ｐｏｒｏｄ常数Ｋ_p＝４．６×１０^-2（ｎｍ^-3），积分不变量Q_s＝１．６３（ｎｍ^-2），比内表面Ｓ_p＝８４ｍ²／ｃｍ³，Ｐｏｒｏｄ半径Ｒ_p＝４．４ｎｍ用通常方法扣除背底后的散射强度不满足Ｐｏｒｏｄ规律。 关键词：     

铁基纳米晶合金的热膨胀研究

研究了铁基纳米晶合金Ｆｅ_１３．５Ｃｕ_１Ｎｂ_３Ｓｉ_１３．５Ｂ_９和Ｆｅ_９１Ｚｒ_７Ｂ_２的热膨胀特性，并与相应成分的非晶合金做了比较。结果表明，在居里温度以下，纳米晶合金的热膨胀系数比非晶合金大得多，而在居里温度以上，两者几乎相等。认为上述的热膨胀的差别可能与铁基非晶态合金中存在的因瓦效应有关。 关键词：     

CH2Br2的同步辐射光电离研究:10—12eV范围内CH2Br2的振动自电离态

报道在超声射流冷却条件下用同步辐射ＶＵＶ光源研究ＣＨ₂Ｂｒ₂的振动自电离结构．根据测量的１０５—１２３ｎｍ范围内母体离子（ＣＨ₂Ｂｒ₂⁺）的光电离产率曲线，获得ＣＨ₂Ｂｒ₂的绝热电离势为１０.２３±０.０１ｅＶ．ＣＨ₂Ｂｒ₂⁺的最低三个电子激发态，即Ａ（²Ａ₂），Ｂ（²Ｂ₁），Ｃ（²Ａ₁）分别位于１０.７８±０.０１ｅＶ，１１.２０±０.０１ｅＶ和１１.２７±０.０１ｅＶ．在１１５.０１—１２１.１５ｎｍ范围内，观察到ＣＨ₂Ｂｒ₂自电离峰叠加在若干台阶结构上，台阶平均宽度为７１６.８±４０.０ｃｍ^-1，对应于ＣＨ₂Ｂｒ₂⁺（Ｘ²Ｂ₂）中Ｂｒ-Ｃ-Ｂｒ反对称的伸缩振动（ｖ₉），所有的峰均归属为收敛于ＣＨ₂Ｂｒ₂⁺（Ｘ²Ｂ₂，ｖ⁺）振动能级的ｎｓ，ｎｐ和ｎｄ自电离Ｒｙｄｂｅｒｇ态．此外，对ＣＨ₂Ｂｒ₂光解离电离产生离子型自由基ＣＨ₂Ｂｒ⁺（Ｘ）的光电离产率曲线的结构也进行了归属 关键词：     

远红外光纤材料(MnF2)x(BaCl2)100-x玻璃结构的EXAFS和WAXS研究

本文用扩展X射线吸收谱(EXAFS)和X射线大角散射谱(WAXS)对远红外光纤材料复合卤化物玻璃(MnF₂)_x(BaCl₂)_166-x(x=65,60,55)的短程结构进行了研究。从MnK吸收限的EXAFS和样品的非晶衍射图,得到了Mn原子的近邻原子配位信息。结果表明F,Cl原子在Mn原子周围形成了混合配位的八面体(MnCl₂F₄),这些八面体以Mn—F键为桥键连成“之”字型 关键词：     

Electroconductivity and pressure–temperature states of step shocked C60 fullerite

A study of electrophysical and thermodynamic properties of C₆₀ single crystals under step shock loading has been carried out. The increase and the following reduction in specific electroconductivity of C₆₀ fullerite single crystals at step shock compression up to pressure 30 GPa have been measured. The equations of state for face centred cubic (fcc) C₆₀ fullerite as well as for two-dimensional polymer C₆₀ and for three-dimensional polymer C₆₀ (3D-C₆₀) were constructed. The pressure–temperature states of C₆₀ fullerite were calculated at step shock compression up to pressure 30 GPa and temperature 550 K. The X-ray diffraction studies of shock-recovered samples reveal a mixture of fcc C₆₀ and a X-ray amorphous component of fullerite C₆₀. The start of the formation of the X-ray amorphous component occurs at a pressure P _m≈ 19.8 GPa and a temperature T _m≈ 520 K. At pressures exceeding P _m and temperatures exceeding T _m, the shock compressed fullerite consist of a two-phase mixture of fcc C₆₀ fullerite and an X-ray amorphous component presumably consisting of the nucleators of polymer 3D-C₆₀ fullerite. The decrease in electroconductivity of fullerite can be explained by the percolation effect caused by the change of pressure, size and number of polymeric phase nuclei.     

X-ray diffraction analysis of C<Subscript>60</Subscript> fullerene powder and fullerene soot

C₆₀ fullerene powder and fullerene soot are examined by the method of small-angle X-ray diffraction. Small-angle diffraction patterns constructed in the Guinier coordinates make it possible to find the radii of inertia of scattering elements. The small-angle diffraction scattering findings agree well with large-angle X-ray diffraction data.     

Intercalation of C60 fullerene crystals with alkali and alkaline-earth metals through self-propagating high-temperature synthesis

A method for rapidly intercalating C₆₀ fullerene crystals has been implemented using self-propagating high-temperature synthesis. The method has been used to intercalate C₆₀ fullerene crystals with alkali (K, Rb) and alkaline-earth (Ca, Ba) metals. The superconducting transition temperatures of the prepared compounds have been measured. The C₆₀ fullerene crystals intercalated with calcium have been investigated using X-ray diffraction.     

Single-crystal structural study of the pressure-temperature-induced dimerization of C<Subscript>60</Subscript>

We present a study by Raman spectroscopy and X-ray diffraction/diffuse scattering of C₆₀ single-crystals treated at high-pressure and high-temperature. This allowed us to obtain structural information on the C₆₀ dimer state which can be considered as an intermediate state in the polymerization process. In the 1-6 GPa pressure range the crystals are primarily formed of dimers with additional minor fractions of monomers, 1D and 2D polymers, as shown by the analysis of the Raman spectra. The dimers are disordered within an average cubic lattice derived from that of the monomer. Single-crystal diffraction patterns reveal a characteristic diffuse scattering intensity distribution which has been simulated by calculating the diffuse scattering produced by dimer and trimer model structures. Satisfactory agreement is obtained for random positional and orientational disorder of the C₆₀-C₆₀ dimers although a small concentration of similarly disordered trimers is likely. In a first approximation the dimer/trimer disorder can be considered as random but various inter-dimer correlations are probably present, as discussed.Received: 3 October 2003, Published online: 19 February 2004PACS: 61.48. + c Fullerenes and fullerene-related materials - 61.43.Bn Structural modeling: serial-addition models, computer simulation - 78.30.Na Fullerenes and related materialsT. Wågberg: Present address: Groupe de Dynamique des Phases Condensées, Université Montpellier II, Place E. Bataillon, CC026, 34095 Montpellier, France     

A DOUBLE-TEMPERATURE-GRADIENT TECHNIQUE FOR THE GROWTH OF PURE C60 SINGLE CRYSTALS FROM THE VAPOR PHASE

Pure C₆₀ single crystals were grown by a sublimation-condensation method in an evacuated dosed quartz tube situated in a double-temperature-gradient furnace. Large C₆₀ single crystals, up to a size of 0.6 mm×1.0 mm×2.0 mm with quite smooth and shiny faces, were obtained. X-ray diffraction, electron diffraction and X-ray morphology were carried out and showed that the quality of large C₆₀ single crystals grown by the double-temperature-gradient technique is excellent. In this paper the experimental results of the growth of large C₆₀ single crystals are reported and the morphological and structural characterizations are discussed in detail.     

On the determination of the volume fraction of the crystalline phase in amorphous-crystalline alloys

The possibility of determining volume fractions of crystalline and amorphous phases of partially crystalline alloys from X-ray diffraction data has been discussed. The crystallization of an amorphous microwire of the Fe_73.9B_13.2Si_10.9C₂ composition has been investigated. The crystallization leads to the formation of α-Fe and Fe(Si). An analysis has been made of the X-ray diffraction patterns recorded for a series of samples with different contents of the crystalline and amorphous phases. The angular range has been determined and the calibration graph has been constructed, which can be used to determine the volume fractions of the amorphous and crystalline components in amorphous-crystalline samples.     

C60 growth on Si(100), GaSe(0001) and GeS(001)

C₆₀ films have been grown in ultra high vacuum on various crystalline substrates and the structure of the films has been investigated by low energy electron diffraction (LEED) and high resolution electron energy loss spectroscopy (HREELS). The C₆₀ films form randomly oriented nanocrystals on Si(100), mesoscopic polycrystals on GaSe(0001) and microscopic single crystals on GeS(001). The vibrational structure of the C₆₀/substrate interfaces is analyzed in detail by HREELS carried out in the dipole and impact scattering regimes. It is shown that the epitaxy of C₆₀ on GeS(001) is induced by the weak van der Waals bonding and the peculiar corrugation of the substrate surface.     

织构C60薄膜的生长与光致发光特性

用Hot Wal方法，在氟金云母单晶上生长出了（111）织构的C₆₀薄膜．用X射线衍射、Raman散射、扫描电子显微镜和原子力显微镜研究了织构C₆₀薄膜的结晶质量和结构特性．测量了织构C₆₀薄膜在室温300K和低温77K的光致发光光谱．对所得结果进行了分析与讨论 关键词：     

Ordering phenomena in C<Subscript>60</Subscript>-tetraphenylphosphonium bromide

The fulleride salt C₆₀-tetraphenylphosphonium bromide is investigated as a function of temperature by single crystal X-ray diffuse scattering and diffraction. At room temperature, the C₆₀ orientational disorder is found to be more complex than previously expected. Moreover, a structural phase transition, due to the C₆₀ orientational ordering, is evidenced around 120 K. Its relation with the stabilization of a static Jahn-Teller effect is discussed. Received 3 November 1999