共查询到20条相似文献,搜索用时 15 毫秒
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采用AIM-8800红外显微镜观察了CdGeAs2晶体的面扫描红外透过图像,分别在2.3~4μm、4~8 μm和8~18μm三个波段对退火前后的CdGeAs2晶片红外透过率和面扫描红外透过图像进行了对比分析,研究了晶体的红外均匀性.结果表明,CdGeAs2晶体在多晶粉末包裹下经450℃退火150 h后,其红外透过率和红外透过均匀性都得到较大程度的改善,其中在2.3 ~4μm和4~8μm波段的改善效果尤为显著;分析了影响晶体红外透过率和均匀性的主要因素,探讨了改善晶体均匀性的可能途径.研究结果对于快速评判CdGeAs2晶片质量具有重要的实用价值. 相似文献
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稀土钴氧化物的磁特性和输运性质强烈依靠稀土离子和它们的精细结构.通过Raman散射研究了稀土离子在两种结构中的作用.当R=La、Ce、Pr、Nd,时,RCoO_3化合物为立方结构(Pm~3m),而对于小离子半径(R=Sm、Eu、Gd和Dy),RCoO_3化合物存在于正交结构中[空间群为Pnma(D_(2h)~(16)),Z=4].按照其晶体结构和Raman行为,将RCoO_3化合物分成三个群体:一组包含La、Ce、Pr、Nd,另一组包含Sm、Eu、Gd、Dy,第三组包含Tm、Yb 、Lu 和Er. 相似文献
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Crystallography Reports - Raman scattering spectra have been investigated in La3Ga5SiO14 langasite crystals with Cr and Fe impurities and La3Ga5.25Ta0.25Si0.5O14 crystalline solid solution. It is... 相似文献
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Mikio Koyano Hirokazu Watanabe Yasuhisa Yamamura Toshihide Tsuji Shin'ichi Katayama 《Molecular Crystals and Liquid Crystals》2013,570(2):33-38
Abstract Raman scattering spectra and magnetic susceptibility are measured in intercalation compounds FexNbS2 (0.159≤x≤0.325). A strong modification of Raman spectra is observed in a sample with x=0.239 (~ 0.25) which is accompanied by 2a × 2a structural change and antiferromagnetic ordering. Some correlations between magnetic ordering (antiferromagnetic or spin glass) and structural change are also discussed for wide range of Fe contents x. 相似文献
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Crystallography Reports - Raman spectra of monodisperse crystalline diamond powders have been studied in dependence of the sample sizes. Raman scattering was excited by a near-IR cw laser (λ0... 相似文献
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用于红外变频的大尺寸AgGaS2晶体生长 总被引:5,自引:4,他引:1
在红外变频非线性光学应用中需要高光学质量大尺寸AgGaS2晶体元件.我们采用改进的Bridgman方法生长直径28mm、长度60~80mm的晶体棒.成功生长的关键是要采用C向籽晶.[001]籽晶生长的晶体中很少发现裂纹、聚片孪晶等宏观缺陷.在Ag2S共存下的热处理能有效地排除晶体中的异相沉淀,显著改善透明度.我们制备的Ⅰ型相位匹配8mm×10mm×16mm和5mm×5mm×15mm?AgGaS2晶体元件分别成功地应用于差频、和频激光实验. 相似文献
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Hiromichi Kataura Yoshinori Kumazawa Noriaki Kojima Yutaka Maniwa Ikurou Umezu Shinichi Masubuchi 《Molecular Crystals and Liquid Crystals》2013,570(1):757-762
Abstract We have measured Raman spectra of bromine doped single-walled carbon nanotubes (SWNTs) using various laser lines to clarify the electronic states of the doped SWNT. In the case of evacuated sample after full doping, two breathing mode peaks were observed simultaneously by visible laser excitations. We assigned the higher frequency peak to the doped SWNT bundles, and the other peak to the undoped portions in the sample. Intensity ratio between them decreased with decreasing excitation energy, and in the infrared region, the breathing mode band of the doped bundle was not observed. These results can be explained by a simple rigid band model. 相似文献
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E. Ehrenfreund Z. Vardeny O. Brafmanand B. Horovitz 《Molecular Crystals and Liquid Crystals》2013,570(1):367-371
The amplitude mode approach for describing the resonant raman scattering in dimerized chains is reviewed and applied to the polyacetylene system. trans-(CH)x is disordered with a variable electron-phonon coupling constant. cis-(CH) x is ordered with an extrinsic gap of ~ 5% of the full gap. A distribution of extrinsic gaps is shown to exist In trans-(CH) x chains in partially isomerized polyacetylene. 相似文献
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本文报道了Sr2+离子掺杂对GdVO4晶体生长和拉曼性能的影响.SrxGd1-xVO4晶体粉末经X射线粉末衍射分析,其结果仍属四方晶系,具有锆英石结构.实验表明,高掺杂浓度时,Sr2+离子不易取代Gd3+离子进入GdVO4晶体的晶格,易导致SrxGd1-xVO4晶体开裂和产生包裹体.XPS实验证明,SrxGd1-xVO4晶体中钒元素为+5价.同时测试了常温下SrxGd1-xVO4晶体的拉曼光谱,发现随着Sr2+离子浓度增加,在884cm-1处的VO4反对称伸缩振动逐渐增强,表明Sr2+离子的掺入影响了GdVO4晶体的拉曼性能. 相似文献
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We report an experimental investigation on the effects of thermal treatments at different temperatures (room—1270 K) and for different duration (0–75 h) on amorphous silica nanoparticles (fumed silica) in powder tablet form. Three types of fumed silica are considered, comprising nearly spherical particles of 40 nm, 14 nm and 7 nm mean diameter. The experimental techniques used here are Raman and infrared absorption (IR) spectroscopy together with atomic force microscopy (AFM). Raman and IR spectra indicate that the structure of nanometer silica particles is significantly different with respect to that of a bulk silica glass. In particular, the main differences regard the positions of the IR band peaked at about 2260 cm?1, the Raman R-band peaked at about 440 cm?1 and the intensity of the D1 and the D2 Raman lines, related to the populations of 4- and 3-membered rings, respectively. Our data also indicate that, under thermal treatments, the structure of fumed silica samples is significantly changed, gradually relaxing towards that pertaining to ordinary bulk silica. These changes are interpreted here on the basis of the morphological information provided by the AFM measurements and assuming a two-shell structure for the fumed silica primary particles. 相似文献
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《Journal of Non》2006,352(52-54):5564-5571
We systematically added WO3 (up to 10 mol%) and P2O5 (up to 16 mol%) in TeO2–BaO–SrO–Nb2O5 (TBSN) glass system and studied thermal and optical properties of the resultant glasses. The dependences of the additive concentration on glass transition (Tg) and crystallization (Tx) temperatures are presented. The TBSN glass added with ⩾4 mol% WO3 and P2O5 showed high stability against crystallization. The changes in optical band gap energy due to WO3 and P2O5 addition was studied using UV–VIS–NIR absorption spectrometry. The WO3 addition shifted the optical band gap to longer wavelengths, whereas P2O5 addition shifted that to shorter wavelengths. Effects of the WO3 and P2O5 addition on the Raman spectra of TBSN glass are clarified. New Raman bands due to WO4 and PO4 tetrahedra formed in the resultant glasses broadened their Raman spectra. Present glasses are characterized by higher thermal stability and wider Raman spectra, therefore, they are promising candidates for fiber Raman amplifiers in photonics systems. 相似文献
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Crystallography Reports - The Raman spectra of multiwall (bamboo-type) carbon nanotubes implanted with nitrogen have been investigated under excitation by different lasers with wavelengths... 相似文献
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Results are presented which show how defects in a nematic liquid crystal can be used to investigate material flow when external electric fields are applied. These results include measurements of the size of flow cells, which were created between the electrodes by an electric field. The electrodes, which were made of transparent conductive coated glass, were placed in a vertical position so that flow cells could be observed from the top while dynamic scattering was observed when viewing normal to the electrodes. 相似文献