Gkowth of YBa2Cu3O7-δ Single Crystals and Films by a Flux and a Sputtering Methods

1987 ◽  
Vol 99 ◽  
Author(s):  
K. Takagi ◽  
M. Hirao ◽  
M. Hiratani ◽  
H. Kakibayashi ◽  
T. Aida ◽  
...  
Keyword(s):  
Single Crystals ◽  
High Resolution Electron Microscopy ◽  
Growth Conditions ◽  
Epitaxial Films ◽  
Electric Resistivity ◽  
Periodic Lattice ◽  
Flux Growth ◽  
Bulk Crystals ◽  
Resolution Electron ◽  
Diffusion Of Impurities

ABSTRACTYBa2Cu3O7-δ single crystals and epitaxial films are grown and characterized. In flux growth for bulk crystals, effects of growth conditions on yield and electric resistivity of crystals are examined. The yield of flaky crystals depends on the formation of cavities. The transition temperature is 86 K after annealing in an oxygen atmosphere. Films are prepared on SrTiO3 by sputtering and epitaxial growth is confirmed by high resolution electron microscopy. Periodic lattice defects are observed near the interface between the substrate and the film. It seems that these defects result from the diffusion of impurities from the substrate.

Structure, Composition and Stability of Heterophase Boundaries

1997 ◽  
Vol 3 (S2) ◽  
pp. 673-674
Author(s):  
M. Rühle ◽  
T. Wagner ◽  
S. Bernath ◽  
J. Plitzko ◽  
C. Scheu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Elevated Temperatures ◽  
Analytical Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
Advanced Materials ◽  
Bulk Crystals ◽  
Transmission Electron ◽  
Resolution Electron ◽  
The Stability

Heterophase boundaries play an important role in advanced materials since those materials often comprise different components. The properties of the materials depend strongly on the properties of the interface between the components. Thus, it is important to investigate the stability of the microstructure with respect to annealing at elevated temperatures. In this paper results will be presented on the structure and composition of the interfaces between Cu and (α -Al2O3. The interfaces were processed either by growing a thin Cu overlayer on α- Al2O3 in a molecular beam epitaxy (MBE) system or by diffusion bonding bulk crystals of the two constituents in an UHV chamber. To improve the adhesion of Cu to α -Al2O3 ultrathin Ti interlayers were deposited between Cu and α - Al2O3.Interfaces were characterized by different transmission electron microscopy (TEM) techniques. Quantitative high-resolution electron microscopy (QHRTEM) allows the determination of the structure (coordinates of atoms) while analytical electron microscopy (AEM) allows the determination of the composition with high spatial resolution.

Dependence of Mo/Si Multilayer Morphology on Deposition Angle

1989 ◽  
Vol 160 ◽  
Author(s):  
Yuanda Cheng ◽  
Mary Beth Stearns ◽  
David J. Smith
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Substrate Temperature ◽  
High Resolution Electron Microscopy ◽  
Growth Conditions ◽  
Columnar Growth ◽  
Cross Sectional ◽  
Resolution Electron ◽  
Deposition Angle

AbstractStudies have been made of the dependence of the structure on the deposition angle and the substrate temperature of a series of Mo/Si multilyers fabricated in a UHV system by e-beam evaporation. The detailed morphology was determined by cross-sectional high resolution electron microscopy. Columnar growth in the crystalline Mo layers was found to follow the tangent rule. The overall quality of the multilayers was found to depend strongly on the growth conditions.

Flux growth conditions of Li2BaP2O7 single crystals

2002 ◽  
Vol 56 (5) ◽  
pp. 787-792 ◽  
Author(s):  
D Ivanova ◽  
V Nikolov ◽  
P Peshev
Keyword(s):  
Single Crystals ◽  
Growth Conditions ◽  
Flux Growth

Preparation and structural characterization of sputtered CoO, NiO, and Ni0.5Co0.5O thin epitaxial films

1991 ◽  
Vol 6 (12) ◽  
pp. 2680-2687 ◽  
Author(s):  
M.J. Carey ◽  
F.E. Spada ◽  
A.E. Berkowitz ◽  
W. Cao ◽  
G. Thomas
Keyword(s):  
Single Phase ◽  
High Resolution Electron Microscopy ◽  
Lattice Parameter ◽  
Epitaxial Films ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Resolution Electron ◽  
Axis Parallel ◽  
Oxide Substrate

Single phase CoO, NiO, and Ni0.5Co0.5O epitaxial films have been prepared by reactive sputtering onto 〈0001〉 α−Al2O3 substrates maintained at 373 K. Epitaxy was confirmed by x-ray diffraction (XRD) and high resolution electron microscopy (HREM) techniques. XRD experiments indicate that these monoxide films are cubic and contain rotation twins with the twin axis parallel to 〈111〉. Lattice parameters for the CoO and NiO films are 0.4254 ± 0.0001 nm and 0.4173 ± 0.0006 nm, respectively, and agree with published values for the corresponding bulk oxides. The lattice parameter 0.4220 ± 0.0001 nm for the Ni0.5Co0.5O film lies between those of CoO and NiO and suggests that the mixed oxide film is compositionally homogeneous. Cross-sectional HREM images of the Ni0.5Co0.5O specimen show Σ3(12) twin boundaries perpendicular to the oxide-substrate interface. The twin regions are approximately 30 nm in size and are uniformly distributed throughout the film. The epitaxial orientation of the monoxide films with respect to the substrate can be summarized by the relationships [111] monoxide // [0001] α−Al2O3, [10] monoxide // [100] α−Al2O3, and [11] monoxide // [110] α−Al2O3.

Microstructure of ELO-GaN Layers Grown by Hydride Vapor Phase Epitaxy

2001 ◽  
Vol 693 ◽  
Author(s):  
Silvija Gradecak ◽  
Volker Wagner ◽  
Marc Ilegems ◽  
Fabienne Bobard ◽  
Pierre Stadelmann
Keyword(s):  
Electron Microscopy ◽  
Vapor Phase ◽  
Vertical Direction ◽  
High Resolution Electron Microscopy ◽  
Growth Conditions ◽  
Vapor Phase Epitaxy ◽  
Hydride Vapor Phase Epitaxy ◽  
Initial Stage ◽  
Resolution Electron ◽  
Microscopy Techniques

AbstractElectron microscopy techniques are applied to investigate structural properties of GaN layers selectively grown by hydride vapor phase epitaxy on crystalline and amorphous GaN seed layers deposited on (0001)Al2O3 substrates. Optimalization of the growth conditions lead to a reduction both of the stacking fault concentration and c-axis tilting in the laterally grown regions. During the lateral growth threading dislocations from the seed layer bend from vertical direction of propagation. Bending behavior depends on the type of the dislocation and on the shape of the GaN film in the initial stage of the growth. Optical properties of laterally grown regions are correlated with the high point-defect incorporation that is revealed by high-resolution electron microscopy.

scholarly journals DNA origami single crystals with Wulff shapes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yong Wang ◽  
Lizhi Dai ◽  
Zhiyuan Ding ◽  
Min Ji ◽  
Jiliang Liu ◽  
...  
Keyword(s):  
Single Crystals ◽  
Three Dimensional ◽  
Building Blocks ◽  
High Resolution Electron Microscopy ◽  
Dna Origami ◽  
High Yield ◽  
Binding Modes ◽  
Resolution Electron ◽  
Ultrathin Layer ◽  
Wulff Shapes

AbstractDNA origami technology has proven to be an excellent tool for precisely manipulating molecules and colloidal elements in a three-dimensional manner. However, fabrication of single crystals with well-defined facets from highly programmable, complex DNA origami units is a great challenge. Here, we report the successful fabrication of DNA origami single crystals with Wulff shapes and high yield. By regulating the symmetries and binding modes of the DNA origami building blocks, the crystalline shapes can be designed and well-controlled. The single crystals are then used to induce precise growth of an ultrathin layer of silica on the edges, resulting in mechanically reinforced silica-DNA hybrid structures that preserve the details of the single crystals without distortion. The silica-infused microcrystals can be directly observed in the dry state, which allows meticulous analysis of the crystal facets and tomographic 3D reconstruction of the single crystals by high-resolution electron microscopy.

Ordered structure formation in the flux-grown Ba(Mg1/3Ta2/3)O3 single crystals

2001 ◽  
Vol 16 (6) ◽  
pp. 1593-1599 ◽  
Author(s):  
Yu-Chang Lee ◽  
Chen-Chia Chou ◽  
Dah-Shyang Tsai
Keyword(s):  
Electron Diffraction ◽  
Single Crystals ◽  
Annealing Time ◽  
High Resolution Electron Microscopy ◽  
Maximum Intensity ◽  
Ordered Structure ◽  
X Ray Diffraction ◽  
Resolution Electron ◽  
Higher Temperature ◽  
Diffraction Patterns

Formation of ordered structure in flux-grown Ba(Mg1/3Ta2/3)O3(BMT) single crystals was studied using x-ray diffraction, electron diffraction, and high-resolution electron microscopy. The low-temperature-grown crystals exhibited no sign of B-site ordering. Annealing at 1500 °C induced the 1:2 ordered phase, and its content increased with the annealing time. The superlattice diffraction peaks were broad initially; they sharpened rapidly with the annealing time. Diffuse superlattice reflections were found in electron diffraction patterns of 1500 °C annealed BMT; they turned into sharp reflections under long annealing time or higher temperature, 1600 °C. The intensity of diffuse reflections was sparsely distributed, but the maximum intensity location was determined in the digitized recording of image plate. The maximum intensity sites of two diffuse reflections in the 〈111〉 direction deviated from the presumed 1/3 and 2/3 positions and shifted towards the center. The diffuse reflection and the deviation from regular positions were interpreted as the composition modulation during B-site cation diffusion.

HREM study of heteroepitaxial interfaces in the Ni.50Co.50O/Al2MgO4(100) system

1992 ◽  
Vol 50 (1) ◽  
pp. 374-375
Author(s):  
W. Cao ◽  
G. Thomas
Keyword(s):  
Electron Microscopy ◽  
Epitaxial Film ◽  
Chemical Vapor ◽  
High Resolution Electron Microscopy ◽  
Epitaxial Films ◽  
Critical Factors ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Film Substrate

Epitaxial CoO/NiO multilayers and alloys have been produced which show interesting structural and magnetic properties. Typically, epitaxial films are grown either by chemical vapor deposition or evaporation. However, sputtering can also yield high quality epitaxial films. The structure of the substrate and the interface of the film/substrate are critical factors to determine the quality of the epitaxial film. The CoO/NiO epitaxial films on the α-Al2O3 had been studied extensively in our previous work. In this paper, the heteroepitaxial interface in the Ni.50Co.50O/Al2MgO4 is studied by using high resolution electron microscopy. Transmission electron microscopy was performed using the JEOL-200CX and JEOL-ARM1000 microscopes at the National Center for Electron Microscopy, Berkeley.

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