PREPARATION OF SINGLE PHASE BISMUTH-BASED 2212 AND 2223 SUPERCONDUCTING OXIDES, AND QUANTITATIVE X-RAY DIFFRACTION ANALYSIS OF 2212 AND 2223 PHASE MIXTURES

Author(s):  
A. BRIGGS ◽  
B.A. BELLAMY ◽  
I.E. DENTON ◽  
J.M. PERKS
2006 ◽  
Vol 301 ◽  
pp. 177-180 ◽  
Author(s):  
Yuichiro Kuroki ◽  
Tomoichiro Okamoto ◽  
Masasuke Takata

Copper aluminum disulfide (CuAlS2) powders were synthesized in an evacuated ampoule at elevated temperatures. X-ray diffraction analysis revealed that the powders heated at temperatures higher than 800oC were single-phase CuAlS2. In the cathodoluminescence (CL) spectra measured at room temperature, the powders heated at temperatures higher than 600oC exhibited a visible emission peak at approximately 1.8 eV and a distinct ultraviolet emission peak at 3.45 eV. The powder heated at 700oC showed the maximum intensity of ultraviolet emission which is considered to be associated with excitons.


2012 ◽  
Vol 508 ◽  
pp. 224-229 ◽  
Author(s):  
Takayuki Yanagida ◽  
Yoshisuke Futami ◽  
Noriaki Kawaguchi ◽  
Jan Pejchal ◽  
Yutaka Fujimoto ◽  
...  

ααΑαNd3+ 0.5% Doped Single Crystal LiCaAlF6 Scintillator Was Grown by the Micro-Pulling down (µ-PD) Method. Powder X-Ray Diffraction Analysis Was Done and the Grown Crystal Was a Single Phase LiCaAlF6. it Was Cut and Polished to the Physical Dimension of 1 × 2 × 7 mm3. in Transmittance Spectrum, Nd3+ 5d-4f Absorption Observed at 175 Nm and the Transmittance Became 80% at Wavelength Longer than 180 Nm. Excited by 160 Nm, Nd3+ 5d-4f Emission Appeared at 180 Nm. X-Ray Induced Radio-Luminescence Spectrum Showed the Similar Feature with the Photoluminescence One. when Coupled with PMT and Irradiated by 241Am α-Ray, the Absolute Light Yield Resulted 100 Ph/5.5 Mev α.


Author(s):  
А.В. Павленко ◽  
Д.В. Стрюков ◽  
Н.В. Тер-Оганесян

For the first time, thin films of NaNbO3 on a MgO(001) substrate, on which a SrRuO3 layer was previously deposited, were obtained by RF cathode sputtering in an oxygen atmosphere. According to x-ray diffraction analysis the films are single phase and single-crystalline. The lattice parameters in the tetragonal approximation for the NaNbO3 and SrRuO3 layers were: с(NaNbO3) = 0.3940(1) nm, a(NaNbO3) = 0.389(1) nm; с(SrRuO3) = 0.4004(1) nm, a(SrRuO3) = 0.392(3) nm. The unit cell deformation for NaNbO3 was ε33 = 0.007, ε11 = 0.002. Dielectric and piezoelectric measurements indicate that the films are in a ferroelectric state.


1987 ◽  
Vol 01 (07n08) ◽  
pp. 323-326 ◽  
Author(s):  
Q.Z. QIN ◽  
A.D. HE ◽  
W.J. JIA ◽  
L.D. MA ◽  
Z.Y. HUA

High Tc superconductivity has been observed in a new U-Y-Ba-Cu-O system at ambient pressure. The zero-resistance temperature in the sample with nominal composition of U0.1Y1.1Ba0.8CuO4−δ is 87K with a width of 2K. X-ray diffraction analysis shows that none of the peaks could be fitted to the uranium oxides and the other raw material structure, and its pattern might be attributed to new multiple phases with structure different from the known single-phase superconducting oxides.


2005 ◽  
Vol 04 (02) ◽  
pp. 237-244 ◽  
Author(s):  
TOSAWAT SEETAWAN ◽  
VITTAYA AMORNKITBAMRUNG ◽  
THANUSIT BURINPRAKHON ◽  
SANTI MAENSIRI

Nanosized powders used for the preparation of bulk Na1.5Co2O4 and Ag -doped Na1.5Co2O4 nanosized crystalline grains were synthesized by the polymerized complex (PC) method. X-ray diffraction analysis revealed that the nondoped and Ag -doped PC products were composed of Co3O4 and Na2CO3 phases. After a subsequent calcination at 800°C, the nondoped PC product was converted to powder of single phase γ- NaxCo2O4 , whereas the Ag -doped PC products remained as mixed phases of Co3O4 and Na2CO3 and Ag2O with a small trace of γ- NaxCo2O4 . SEM and TEM investigations showed that all the calcined products were powders of about 200–500 nm particle size.


2007 ◽  
Vol 14 (02) ◽  
pp. 277-281
Author(s):  
YANXIA DING ◽  
GUANGDA HU ◽  
SUHUA FAN

La modified CBTi ( CLBTi ) thin films were prepared on Pt/Ti/SiO 2/ Si (100) substrates by a sol–gel technique. X-ray diffraction analysis showed that single phase of CLBTi thin films were obtained. Their crystallization and hysteresis behavior were strongly dependent on the La contents. An increase of 2Pr as well as a decrease of 2Ec with the increase of La concentration were observed. The leakage properties of CBTi thin films were found to be improved by the La doping. The results were discussed with respect to the effects of La 3+ substitution at perovskite A-site.


Author(s):  
Edgar S. Etz ◽  
Thomas D. Schroeder ◽  
Winnie Wong-Ng

We are investigating by Raman microprobe measurements the superconducting and related phases in the LnBa2Cu3O7-x (for x=0 to 1) system where yttrium has been replaced by several of the lanthanide (Ln = Nd,Sm,Eu,Ho,Er) elements. The aim is to relate the observed optical spectra (Raman and fluorescence) to the compositional and structural properties of these solids as part of comprehensive materials characterization. The results are correlated with the methods of synthesis, the processing techniques of these materials, and their superconducting properties. Of relevance is the substitutional chemistry of these isostructural systems, the differences in the spectra, and their microanalytical usefulness for the detection of impurity phases, and the assessment of compositional homogeneity. The Raman spectra of most of these compounds are well understood from accounts in the literature.The materials examined here are mostly ceramic powders prepared by conventional solid state reaction techniques. The bulk samples are of nominally single-phase composition as determined by x-ray diffraction.


Author(s):  
L. A. Giannuzzi ◽  
A. S. Ramani ◽  
P. R. Howell ◽  
H. W. Pickering ◽  
W. R. Bitler

The δ phase is a Zn-rich intermetallic, having a composition range of ∼ 86.5 - 92.0 atomic percent Zn, and is stable up to 665°C. The stoichiometry of the δ phase has been reported as FeZn7 and FeZn10 The deviation in stoichiometry can be attributed to variations in alloy composition used by each investigator. The structure of the δ phase, as determined by powder x-ray diffraction, is hexagonal (P63mc or P63/mmc) with cell dimensions a = 1.28 nm, c = 5.76 nm, and 555±8 atoms per unit cell. Later work suggested that the layer produced by hot-dip galvanizing should be considered as two distinct phases which are characterized by their morphological differences, namely: the iron-rich region with a compact appearance (δk) and the zinc-rich region with a columnar or palisade microstructure (δp). The sub-division of the δ phase was also based on differences in diffusion behavior, and a concentration discontinuity across the δp/δk boundary. However, work utilizing Weisenberg photographs on δ single crystals reported that the variation in lattice parameters with composition was small and hence, structurally, the δk phase and the δp phase were the same and should be thought of as a single phase, δ. Bastin et al. determined the average cell dimensions to be a = 1.28 nm and c = 5.71 nm, and suggested that perhaps some kind of ordering process, which would not be observed by x-ray diffraction, may be responsible for the morphological differences within the δ phase.


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