Structural and superconducting properties of melt-grown Y–Ba–Cu–O superconductors

1996 ◽  
Vol 11 (10) ◽  
pp. 2406-2415 ◽  
Author(s):  
R. Gopalan ◽  
T. Rajasekharan ◽  
T. Roy ◽  
G. Rangarajan ◽  
V. Ganesan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Strain Field ◽  
Crack Width ◽  
Growth Process ◽  
Critical Radius ◽  
Radius Of Curvature ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

YBa2Cu3O7 (123) samples with varying Y2BaCuO5 (211) concentrations (0 mol%, 20 mol%, 28 mol%, and 50 mol%) were synthesized by the melt-growth process. Microstructural characterizations were done using x-ray diffraction (XRD), optical microscopy, scanning electron microscopy, and transmission electron microscopy (TEM). It was found that 123 platelet width, crack width between the platelets, and 211 particle size decreased systematically with increasing 211 concentration. TEM study showed that there is a critical radius of curvature (rc ≤ 0.2 μm-0.3 μm) of the 123/211 interface where defects/contrasts of strain field start to appear, and these defects are believed to be responsible for pinning the magnetic flux. Microhardness measurements showed that Vickers hardness (VHN) increases with increasing 211 content. Critical current density (Jc) values obtained from magnetization measurements using a SQUID magnetometer were found to increase in melt-grown samples by the addition of 211 content.

Growth and Characterization of Misostructural Zinc Oxide Tubes

2005 ◽  
Vol 23 ◽  
pp. 293-296
Author(s):  
X.W. Sun ◽  
C.X. Xu ◽  
B.J. Chen ◽  
Y. Yang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Zinc Oxide ◽  
Growth Process ◽  
Hexagonal Structure ◽  
Metallic Zinc ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

Zinc oxide (ZnO) microtube has been fabricated by heating the mixture of ZnO and graphite powders in the atmosphere. The ZnO microtubes showed perfect hexagonal profiles with bell-mouth or normal hexagonal tops. Both X-ray diffraction (XRD) and high-resolution transmission electron microscopy (TEM) demonstrated that the product was composed of ZnO with typical hexagonal structure grown predominantly along (002) direction. The growth process was interpreted by means of vaporliquid-solid mechanism combining with the evaporation of metallic zinc.

Solvothermal Synthesis and Electrochemical Properties of Hairball-Like Bismuth Trisulphide Microcrystallines

2011 ◽  
Vol 233-235 ◽  
pp. 2289-2293
Author(s):  
Pin Jiang Li ◽  
Wen Jun Fa ◽  
Yan Ge Zhang ◽  
Bao Jun Huang ◽  
Yi Dong Zhang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Solvothermal Synthesis ◽  
Growth Process ◽  
Solvothermal Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
One Step ◽  
Scanning Electron

Hairball-like bismuth trisulphide microcrystallines has been successfully prepared via one step solvothermal process and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) techniques. The morphologies of the Bi2S3 microcrystallines were influenced by reaction time, temperature, the mole ratio of the reactants and concentration of starting materials, and the growth process has been proposed. The electrochemical behavior of Bi2S3 was investigated using the cyclic voltammetry.

THERMAL EVAPORATION SYNTHESIS OF ZnO MICROSHELLS

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2722-2727
Author(s):  
Y. J. XING ◽  
D. P. YU ◽  
Z. H. XI ◽  
Z. Q. XUE
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Zinc Oxide ◽  
Growth Process ◽  
Thermal Evaporation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

We demonstrate the synthesis of zinc oxide microshells by thermal evaporation of ZnO and Zn powders. X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) observations reveal that the products are ZnO microshells with hollow cores, of which the wall thickness is about several hundred nanometers. The possible growth process is discussed.

ZnO/Graphene Composites: Synthesis, Characterization and Optical Properties

2014 ◽  
Vol 609-610 ◽  
pp. 76-81 ◽  
Author(s):  
Ling Wei Hu ◽  
Hua Tian ◽  
Yu Xia Zhang ◽  
Kun Lu ◽  
Ai Hua Jing
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Growth Process ◽  
Gas Sensing ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
Transmission Electron ◽  
Potential Applications ◽  
Scanning Electron

ZnO/graphene composites has been synthesized using a one-pot hydrothermal method at moderate temperature of 90°C. Hydrothermal growth was done in an aqueous solution consisting of 20 mL graphene oxide (GO) solution (0.25 mg/mL) with equimolar of zinc acetate [ZAc, Zn (CH3COO)2·2H2 and hexamethylenetetramine (HMTA, C6H12N4). The as-synthesized composites was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy. The results of the characterization indicate that GO was reduced to graphene in the growth process, while ZnO in the form of quantum dots (QDs) or nanoparticles embedded in the graphene sheet. The composites synthesized by this method will have potential applications in bioimaging, gas sensing, optoelectrical materials and devices. The photoluminescence (PL) of the conposites was also investigated.

V2O5 Nanorods with Improved Cycling Stability for Li Intercalation

2009 ◽  
Vol 1170 ◽  
Author(s):  
Alexey M Glushenkov ◽  
Vladimir I. Stukachev ◽  
Mohd Faiz Hassan ◽  
Gennady G. Kuvshinov ◽  
Hua Kun Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Energy Minimization ◽  
Scanning Transmission Electron Microscopy ◽  
Growth Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Spin Resonance ◽  
Scanning Transmission ◽  
Oxidation Surface

AbstractWe have recently reported a solid-state, mass-quantity transformation from V2O5 powders to nanorods via a two-step approach [1]. In this paper we present detailed investigation of the growth process using x-ray diffraction, scanning/transmission electron microscopy and electron spin resonance. The growth of nanorods at intermediate stages has been examined. Oxidation, surface energy minimization and surface diffusion play important roles in the growth mechanism.

Microstructure and superconducting properties of Y–Ba–Cu–O and Yb–Ba–Cu–O thin films formed by metalorganic deposition

1989 ◽  
Vol 4 (5) ◽  
pp. 1065-1071 ◽  
Author(s):  
Y. L. Chen ◽  
J. V. Mantese ◽  
A. H. Hamdi ◽  
A. L. Micheli
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Grain Size ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Furnace Annealing ◽  
X Ray ◽  
Conventional Furnace ◽  
Transmission Electron ◽  
Metalorganic Deposition

Thin films of Y–Ba–Cu–O and Yb–Ba–Cu–O, 0.5–1.5 μm in thickness, were deposited onto (211) and (100) SrTiO3 single crystal substrates by metalorganic deposition (MOD). After deposition the samples were annealed either by conventional furnace annealing or rapid thermal annealing (RTA). The microstructures of these films were then characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive x-ray spectrometry (EDS). Grain size of the annealed films varied from 0.25 to 1.0 μm. Improved superconducting properties were found for the RTA samples, compared to furnace annealing, and were attributed to larger grain size, little strontium diffusion into the thin films from the substrate, and highly preferred orientation of the 1:2:3 phase.

Synthesis and Microstructures of α-Fe2O3 Bicrystalline Nanowires

2004 ◽  
Vol 839 ◽  
Author(s):  
R.M. Wang ◽  
Y.F. Chen ◽  
Y. Y. Fu ◽  
H. Zhang ◽  
C. Kisielowski
Keyword(s):  
Electron Microscopy ◽  
Growth Process ◽  
Oxidation Process ◽  
Solid Phase ◽  
X Ray Diffraction ◽  
Phase Growth ◽  
X Ray ◽  
Numerical Reconstruction ◽  
Transmission Electron ◽  
High Resolution Tem

ABSTRACTNovel Fe2O3 nanowires have been successfully synthesized by a simple oxidation process of pure iron. The microstructure of the Fe2O3 nanowires have been systematically investigated by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM). The investigated materials are found to be stoichiometric rhombohedral α-Fe2O3 with typical diameters of 20–80 nm and lengths up to 20 μm. In addition to known single crystal Fe2O3 nanowires, a great amount of novel bicrystalline nanowires were found with ellipsoidal heads. Investigations indicate that most of the bicrystalline nanowires are twins and their orientation relationship is obtained to be (−1, 1, 10)M//(−1, 1, 10)T, [110]M//[-1-10]T. High resolution TEM with numerical reconstruction of the electron exit wave was used to investigated the atomic structure of the micro-twins. Their growth mechanism is briefly discussed on the basis of solid phase growth process.

A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

1982 ◽  
Vol 40 ◽  
pp. 722-723 ◽  
Author(s):  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

The Effect of the Microstructure of Diffusion Barriers on the Palladium Activation for Electroless Copper Deposition

2002 ◽  
Vol 716 ◽  
Author(s):  
Seok Woo Hong ◽  
Yong Sun Lee ◽  
Ki-Chul Park ◽  
Jong-Wan Park
Keyword(s):  
Electron Microscopy ◽  
Diffusion Barriers ◽  
Copper Deposition ◽  
X Ray Diffraction ◽  
Plan View ◽  
X Ray ◽  
Transmission Electron ◽  
Electroless Copper ◽  
Sheet Resistance Measurement ◽  
Scanning Electron

AbstractThe effect of microstructure of dc magnetron sputtered TiN and TaN diffusion barriers on the palladium activation for autocatalytic electroless copper deposition has been investigated by using X-ray diffraction, sheet resistance measurement, field emission scanning electron microscopy (FE-SEM) and plan view transmission electron microscopy (TEM). The density of palladium nuclei on TaN diffusion barrier increases as the grain size of TaN films decreases, which was caused by increasing nitrogen content in TaN films. Plan view TEM results of TiN and TaN diffusiton barriers showed that palladium nuclei formed mainly on the grain boundaries of the diffusion barriers.

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