共查询到20条相似文献,搜索用时 31 毫秒
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Jie Zhang Bing Han Pengju Li Yang Bian Jianliang Li Hengzhen Shi 《Journal of Materials Science: Materials in Electronics》2014,25(8):3498-3503
This work first reports the synthesis and luminescence properties of rare earth Ce3+, Eu2+, Eu3+ ions doped β-Zn3BPO7 phosphors [β-Zn3BPO7:Ln (Ln = Ce3+, Eu2+, Eu3+)]. The phosphors were synthesized by a solid-state reaction at high temperature, and their luminescence properties were investigated by measuring the photoluminescence excitation and emission spectra. The f–d transitions of Ce3+ and Eu2+ ions in the host lattice are assigned and corroborated, which lead to the broad emission band in ultraviolet (UV) and visible region for Ce3+ and Eu2+ ions under UV excitation, respectively. Typical reddish orange emission from Eu3+ in the host lattice was also observed. The spectroscopic characteristics including Stokes shift, crystal field depression, electron–vibrational interaction, and charge transfer band were investigated and compared with that in other borophosphate phosphors. β-Zn3BPO7:Eu2+ and β-Zn3BPO7:Eu3+ phosphors show potential application in solid state lighting region. 相似文献
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Li'an HAN Huaping YANG Yongjun HE 《材料科学技术学报》2008,24(5):709-711
Lattice effect on magnetic and electrical transport properties of Ln2/3Pb1/3MnO3 (Ln=La, Pr, Nd) films prepared by RF magnetron sputtering technique were investigated. With the decrease of the average ions radius 〈rA〉, the structure of Ln2/3Pb1/3MnO3 (Ln=La, Pr, Nd) targets transit from the rhombohedral phase to the orthorhombic phase, and the Curie temperature reduces rapidly with the decrease of 〈rA〉. The electrical properties show that films are the metallic state which can be fitted to the formula: ρ(T)=ρ0 + ρ1T^2 + ρ2T^4.5 at low temperatures. The temperature range of the ferromagnetic metallic state becomes narrow with the decrease of 〈rA〉. The phenomenon can be explained by the lattice effect. 相似文献
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The Y3+/Ho3+, Y3+/Dy3+, and Dy3+/Ho3+ interdiffusion coefficients in the YBa2Cu3O7 ? δ-HoBa2Cu3O7 ? δ, YBa2Cu3O7 ? δ-DyBa2Cu3O7 ? δ, and DyBa2Cu3O7 ? δ-HoBa2Cu3O7 ? δ systems have been determined in air at a temperature of 1233 K by the Boltzmann-Matano method from the yttrium/holmium, yttrium/dysprosium, and dysprosium/holmium concentration profiles across the diffusion zone between two pellets of the high-T c superconductors. The composition dependences of the interdiffusion coefficients in the solid-solution systems are presented. 相似文献
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LuTaO4是一种新型的辐射探测材料, 但是制备高质量的透明薄膜面临着巨大挑战。为了在保证薄膜不开裂与高透明度的前提下提高薄膜的厚度, 通过大量摸索选用聚乙烯吡咯烷酮(PVP)为胶黏剂并优化溶胶中固含量及PVP含量成功制备出单层厚度达到100 nm的LuTaO4:Ln3+(Ln=Eu,Tb)薄膜, 保证了薄膜的透明度同时大大提高了发光性能。该方法为高质量LuTaO4:Ln3+(Ln=Eu,Tb)厚膜的制备和应用奠定了基础。 相似文献
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在修正各二元素的基础上研究了Y2O3-SrO-V2O5和Nd2O3-SrO-V2O5三元系统的相关系,并提出了它们的亚固相图。在后一系统中发现了一个新相Nd8SrV3O20.5。在近Nd2O3-SrO二元系处发现一个三元固溶区。 相似文献
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Shujuan Zhuo Mingwang Shao Hongyan Xu Tao Chen Dorthy Duo Duo Ma Shuit-Tong Lee 《Journal of Materials Science: Materials in Electronics》2013,24(1):324-330
The interaction of the surface plasmons of gold nanoparticles on silicon nanowires with fluorophores, lanthanide ions (praseodymium ions, Pr3+, neodymium ions Nd3+, holmium ions Ho3+, and erbium ions Er3+) was investigated. In the presence of Au/Si nanomaterials, the fluorescence peaks were significantly enhanced, which resulted in about 2 orders of magnitude enhancement. The photoluminescence studies revealed that the enhanced fluorescence originates from the local field enhancement around Ln3+ ions, caused by the electronic plasmons resonance of the gold nanoparticles. Results showed that this Au/Si nanostructure had larger enhancement factor than that caused by unsupported Au nanoparticles. These results might be explained by the local field overlap originated from the closed and fixed gold nanoparticles on silicon nanowires. 相似文献
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《International Journal of Inorganic Materials》1999,1(3-4):281-287
We refer here to the electrical and magnetic properties of the Ln1−xMxCoO3 systems (Ln3+: La3+, M2+: Ca2+, Sr2+, Ba2+; Ln3+: Nd3+, M2+: Sr2+), paying special attention to those ferromagnetic compounds that display M–I transitions as temperature rises: La1−xMxCoO3 (M2+: Ca2+, Sr2+, Ba2+) in the compositional interval x=0.2–0.3, and Nd1−xSrxCoO3, with x=0.40. The magneto-transport properties of such materials are peculiar and interesting: they show diodic behavior and large relaxation effects — these latter being specially important in the Nd compound — they display magnetoresistive effects specially at the M–I transition temperatures, and they age with time. All these results are discussed on the basis of the inhomogeneous electronic structure of these doped cobalt perovskites and taking into account the influence of the lanthanide ion on their magnetic and electrical properties. 相似文献
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Tricolor emission Ca2SiO4:Ln (Ln = Ce3+, Eu2+, Sm3+) phosphors were synthesized by the conventional solid-state reaction method, and their photoluminescence properties were investigated. Ce3+-, Eu2+-, or Sm3+-doped Ca2SiO4 phosphors showed typical blue, green, or red luminescence in the CIE1931 chromaticity diagram, respectively. In addition, the luminescence efficiency of the tricolor emission Ca2SiO4:Ln (Ln = Ce3+, Eu2+, Sm3+) phosphors was evaluated. A series of white light-emitting diode (LED) prototypes were fabricated by combining near-UV LED chip and the as-prepared tricolor emission phosphors with various ratios in weight. White LED prototypes with tunable correlated color temperature and color-rendering index values were realized by controlling the amount of phosphors. The presented results indicated the potential application of Ca2SiO4:Ln (Ln = Ce3+, Eu2+, Sm3+) phosphors in near-UV white LED. 相似文献
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用于燃料电池的Ln1—xSrxMnO3系阴极材料的研究 总被引:5,自引:2,他引:3
用固相反应合成了Ln1-xSrxMnO3系钙钛矿型多元氧化物,用X光衍射分析测定了反应产物 相组成和结构类型。离子半径〉0.1A的Pr,Nd,Sm,Gd等取代后的Ln1-xSrxMnO3仍具有正交LaMnO3的结构,而离子半径〈0.95A的Y和Yb取代后的产物,则为六方结构(Yb,Y)MnO3及第二相Sr(Yb,Y)2O4。还测定了产物的烧结性能的电导率。发现(Pr,Nd,Sm)1-xSrxMnO 相似文献
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Ln0.6Sr0.4 FeO3-δ(Ln=La、Nd、Ce)阴极材料的制备与表征 总被引:3,自引:0,他引:3
以甘氨酸-硝酸盐水溶液为前驱体合成了Sr掺杂的稀土铁酸盐Ln0.6Sr0.4FeO3-δ(Ln=La、Nd、Ce)粉体.对制备过程的化学键变化、样品的热稳定性、物相形成过程及导电性进行了表征.结果表明,甘氨酸-硝酸盐合成法成相温度低于1000℃.坯体烧结较粉状样品更有利于钙钛矿物相的形成,La0.6Sr0.4FeO3-δ及Nd0.6Sr0.4FeO3-δ坯体1000℃煅烧2h即可形成近乎单一的钙钛矿相(ABO3);Ce0.6 Sr0.4 FeO3-δ是CeO2立方萤石相和产物钙钛矿相共存,两相难分主次.合成样品低温下的导电行为符合小极化子导电机制;1200℃烧结的La0.6Sr0.4FeO3-δ样品在测试全温度范围内(450~800℃)电导率超过100S/cm,Nd0.6Sr0.4FeO3-δ在中温区(600~800℃)电导率>60S/cm;Ce0.6Sr0.4FeO3-δ样品的电导率不理想. 相似文献
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本语文通过共沉淀工艺合成了复合氧化物Ln0.67Sr0.33MnO3(Ln=La、Pr、Nd、Sm)与传统陶瓷制备方法相比,成相温度降低约450℃,经X射线衍射分析表明,所得复合氧化物为立方钙钛矿结构,晶胞参数随稀土离子半径变化而呈规律性变化,样品的四极法电阻率测试结果表明;样品中的稀土离子Ln的离子半径对其本身的地电性起决定性的作用,应用双交换理论,样品中的稀土离子Ln的离子半径对其本身的导电性 相似文献
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O. S. Petrova E. V. Yakubovich G. P. Murav'eva V. A. Ketsko A. L. Il'inskii N. N. Oleinikov 《Inorganic Materials》2004,40(9):985-988
Ln0.6Sr0.4Co0.8Fe0.2O3 – (Ln = La, Pr, Nd, Sm) solid solutions are prepared by a procedure which makes it possible to markedly reduce the synthesis temperature and duration. X-ray diffraction, microstructural analysis, and density measurements are used to optimize conditions for the fabrication of dense substituted-cobaltite ceramics. 相似文献
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ZrO2 (3 mol% Y2O3) tetragonal and t-ceramics (displacively formed ceramics) were compared with ZrO2 ceramics (3 mol% Ln2O3, where Ln=La, Pr, Nd, Sm, Gd, Tb, Dy, Er, or Yb) processed in an identical manner. Sintering at 1500 °C for 2 h produced mainly tetragonal polytypes for the dopants with smaller ionic radii than Dy(i.e., Er, Y and Yb) but when ZrO2 was reaction sintered with dopants with larger ionic radii excessive monoclinic phase transformation and associated microcracking resulted. High-temperature annealing in the cubic stability regime and rapid cooling through the tetragonal stability regime was used to fabricate t-composites of ZrO2 doped with Y, Yb, Er or Dy. Room-temperature fracture toughness and strength values are explained on the basis of a ferroelastic-cubic-to-tetragonal transformation. The domain structure was viewed by transmission optical microscopy (TOM) or transmission electron microscopy (TEM). 相似文献
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E. M. Godzhaev E. A. Allakhyarov Kh. S. Khalilova A. M. Suleimanova 《Inorganic Materials》2003,39(7):676-679
The electrical conductivity and Hall coefficient of TlInSe2Ln (Ln = Eu, Yb, Sm) were measured between 300 and 900 K. The results were used to determine the band gap, ionization energy of impurities, conductivity type, and Hall mobility of charge carriers in TlInSe2Ln. The temperature at which the Hall coefficient changes sign is shown to increase with doping level. 相似文献
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D. D. Khalyavin A. P. Sazonov I. O. Troyanchuk R. Szymczak H. Szymczak 《Inorganic Materials》2003,39(10):1092-1096
Data are presented on the structural and magnetic properties of Ln1 – x
Ba
x
CoO3 – (Ln = Nd, Sm; 0 < x 0.66) samples slowly cooled in air after synthesis. The composition stability limits of the intermediate phases Ln1 – y
Ba1 + y
Co2O5 + and solid solutions are determined. The magnetic phase diagram of the Nd1 – x
Ba
x
CoO3 – system is constructed. 相似文献
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