Semi-Coherent Yttria Inclusions Occurring Spontaneously in YBa2Cu3O6+× Films Grown by Dc Magnetron Sputtering

1992 ◽  
Vol 275 ◽  
Author(s):  
T. I. Selinder ◽  
Z. Han ◽  
U. Helmersson ◽  
J. Magnusson ◽  
P. Norling ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Magnetron Sputtering ◽  
Critical Current ◽  
Film Growth ◽  
Number Density ◽  
Dc Magnetron Sputtering ◽  
High Quality ◽  
Transmission Electron ◽  
Current Densities

ABSTRACTSemi-coherent Y2O3 (yttria) inclusions have been observed in high quality, c-axis oriented YBa2Cu3O6+×,(YBCO) Alms. The inclusions were studied by transmission electron microscopy (TEM), and were found to be embedded in the YBCO matrix without disturbing its structure seriously. Their number density is estimated to higher than 2 × 1016 cm−3 in epitaxial YBCO films, having transport critical current densities in excess of 1 × 106 A cm−2 at 77 K. Magnetization measurements indicate a possible correlation between a high density of yttria inclusions and high pinning strength. The effects of the inclusions on film growth and microstructure is discussed.

scholarly journals Transmission Electron Microscopy Study of Magnetic Domain of Cobalt-Samarium Thin Films Fabricated Using DC Magnetron Sputtering Technique

2016 ◽  
Vol 1 ◽  
Author(s):  
Erwin Amiruddin
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Magnetron Sputtering ◽  
Magnetic Domain ◽  
Domain Size ◽  
Microscopy Study ◽  
Dc Magnetron Sputtering ◽  
Transmission Electron ◽  
High Loop

<p>Alloys of cobalt samarium (Co-Sm) in the form of thin films were fabricated using dc magnetron sputtering technique. The films were fabricated as a function of samarium concentration ranging from 0 to 28 at.% in order to investigate the relationship between microstructure, coercivity and magnetic domain structure. Magnetic domain structures in the films have been studied by Lorentz microscopy using transmission electron microscopy (TEM). In this technique, the TEM was operated in the defocused mode. The results show that the magnetic image of Co<sub>90</sub>Sm<sub>10 </sub>film has fairly coarse structure with magnetization ripple and the domains ranging over 200-300 nm. The domain size is much larger than the grain size of Co<sub>90</sub>Sm<sub>10</sub> film. The “multiparticle” or interaction domains suggested that there is strong exchange coupling between the magnetization of the neighbouring grains inside each of them. The hysteresis loop for this film shows a small coercivity with high magnetization value and high loop squareness, indicating a greater proportion of magnetic material. </p>

Low-Tc phase formation at the grain boundaries and electromagnetic granularity in (Bi,Pb)2Sr2Ca2Cu3Ox silver-sheathed tapes

1993 ◽  
Vol 51 ◽  
pp. 940-941
Author(s):  
Yi Feng ◽  
A. Umezawa ◽  
H. S. Edelman ◽  
D. C. Larbalestier
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Boundaries ◽  
Critical Current ◽  
Ac Susceptibility ◽  
Transmission Electron ◽  
Heat Treated ◽  
Standard Powder ◽  
Current Densities ◽  
Powder In Tube

High resolution transmission electron microscopy (HRTEM) was performed on progressively heat treated Ag-clad (Bi,Pb)2Sr2Ca2Cu3Ox (2223) tapes and was correlated with their transport critical current densities, DC magnetization and AC susceptibility. HRTEM reveals the presence of a small number of half layers of the low Tc Bi2Sr2CaCu2Ox (2212) phase clustered at the numerous (001) twist grain boundaries. This residual 2212 phase produces electromagnetic granularity in a temperature range around 77K and thus directly controls the critical current.The Bi(Pb)-Sr-Ca-Cu-0 (BSCCO) Ag-clad tapes with the stoichiometric 2:2:2:3 starting composition were prepared by a standard powder-in-tube method. Sample A was heat treated at 817°C for 5 hours only. Sample B was first heat treated at 817°C for 24 hours, and then heat treated for 100 hours at the same temperature after two intermediate pressings. Sample C was heat treated at 830°C for 72 hours, and then heat treated for additional 196 hours after one intermediate pressing.

scholarly journals Transmission Electron Microscopy Study of Magnetic Domain of Cobalt-Samarium Thin Films Fabricated Using DC Magnetron Sputtering Technique

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Erwin Amiruddin
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Magnetron Sputtering ◽  
Magnetic Domain ◽  
Domain Size ◽  
Microscopy Study ◽  
Dc Magnetron Sputtering ◽  
Transmission Electron ◽  
High Loop

<p>Alloys of cobalt samarium (Co-Sm) in the form of thin films were fabricated using dc magnetron sputtering technique. The films were fabricated as a function of samarium concentration ranging from 0 to 28 at.% in order to investigate the relationship between microstructure, coercivity and magnetic domain structure. Magnetic domain structures in the films have been studied by Lorentz microscopy using transmission electron microscopy (TEM). In this technique, the TEM was operated in the defocused mode. The results show that the magnetic image of Co<sub>90</sub>Sm<sub>10 </sub>film has fairly coarse structure with magnetization ripple and the domains ranging over 200-300 nm. The domain size is much larger than the grain size of Co<sub>90</sub>Sm<sub>10</sub> film. The “multiparticle” or interaction domains suggested that there is strong exchange coupling between the magnetization of the neighbouring grains inside each of them. The hysteresis loop for this film shows a small coercivity with high magnetization value and high loop squareness, indicating a greater proportion of magnetic material. </p>

Transmission Electron Microscopy of Pb-doped Bi2Sr2Ca2Cu30x /Ag composite conductors prepared by the two-powder process: The effect of lead addition on critical current and microstructure

1994 ◽  
Vol 52 ◽  
pp. 798-799
Author(s):  
J. S. Luo ◽  
S. E. Dorris ◽  
M. T. Lanagan ◽  
V. A. Maroni
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Critical Current ◽  
Phase Evolution ◽  
Specific Method ◽  
X Ray ◽  
Transmission Electron ◽  
Composite Conductors ◽  
Current Densities ◽  
Lead Addition

Recent studies indicate that a more uniform and more fully reacted Pb-doped Bi2Sr2Ca2Cu3Ox (Bi-2223)phase can be reproducibly obtained within silver sheaths using a two-powder precursor in which the formation of Bi-2223 primarily involves reaction between lead-doped Bi2Sr2CaCu2Oz (Bi-2212) and other non-superconducting phases. In particular, the specific method of introducing lead was reported to significantly influence the phase evolution and superconducting properties of Bi-2223/Ag composite conductors.2 Composites made from lead-doped Bi-2212, where lead is fully incorporated into the Bi-2212 phase prior to its conversion to Bi-2223, exhibit sharper transition temperatures and higher critical current densities than those where lead is added in the form of non-superconducting PbO or Ca2PbO4 phases (Fig. I).2 In this paper, we present a combined investigation by transmission electron microscopy(TEM) and energy dispersive x-ray spectroscopy (EDX) of the composition and microstructure of the (Bi-2223)/Ag composite conductors. The observed differences are discussed with respect to the measured electrical properties.

Influence of antiphase boundaries on critical current densities in Yba2Cu3O7−ysingle crystals

2001 ◽  
Vol 16 (7) ◽  
pp. 1935-1941 ◽  
Author(s):  
Junko Shibata ◽  
Akihiro Oka ◽  
Teruo Izumi ◽  
Yuh Shiohara ◽  
Tsukasa Hirayama ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Single Crystals ◽  
Critical Current ◽  
High Magnetic Field ◽  
Peak Effect ◽  
Antiphase Boundaries ◽  
Transmission Electron ◽  
Current Densities

Twinned and detwinned Yba2Cu3O7−y (Y123) single crystals were observed by transmission electron microscopy to investigate the influences of the lattice defects on the peak effect for Y123 single crystals. Twin boundaries with the spacing of 0.2–0.5 μm were seen only in the twinned Y123 single crystals. Antiphase boundaries (APBs) along the (110)Y123 plane were observed in both twinned and 0.5h-detwinned samples, which showed the peak effect in high magnetic field over 3 T at 70 K. In contrast, APBs were not found in 100h-detwinned sample. Critical current densities of this sample were small all over the range of the applied magnetic field. In conclusion, we suggest that APBs have a significant influence on the peak effect of Y123 single crystals in the high magnetic field.

scholarly journals Digital Imaging: When Should One Take The Plunge?

1997 ◽  
Vol 5 (4) ◽  
pp. 14-15
Author(s):  
John F. Mansfield
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Optical Microscopy ◽  
Digital Imaging ◽  
High Quality ◽  
Storage Devices ◽  
Major Benefit ◽  
Transmission Electron ◽  
Scanning Electron

The current imaging trend in optical microscopy, scanning electron microscopy (SEM) or transmission electron microscopy (TEM) is to record all data digitally. Most manufacturers currently market digital acquisition systems with their microscope packages. The advantages of digital acquisition include: almost instant viewing of the data as a high-quality positive image (a major benefit when compared to TEM images recorded onto film, where one must wait until after the microscope session to develop the images); the ability to readily quantify features in the images and measure intensities; and extremely compact storage (removable 5.25” storage devices which now can hold up to several gigabytes of data).

scholarly journals High quality ultrafast transmission electron microscopy using resonant microwave cavities

2018 ◽  
Vol 188 ◽  
pp. 85-89 ◽  
Author(s):  
W. Verhoeven ◽  
J.F.M. van Rens ◽  
E.R. Kieft ◽  
P.H.A. Mutsaers ◽  
O.J. Luiten
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Quality ◽  
Microwave Cavities ◽  
Transmission Electron

Microstresses in Molybdenum Nitride Thin Films Deposited by Reactive DC Magnetron Sputtering

2005 ◽  
Vol 490-491 ◽  
pp. 589-594 ◽  
Author(s):  
Yao Gen Shen
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Film Growth ◽  
Nitrogen Addition ◽  
Molybdenum Nitride ◽  
Dc Magnetron Sputtering ◽  
Cross Sectional ◽  
Dense Microstructure ◽  
Transmission Electron ◽  
Complete Relaxation

Thin films of molybdenum nitride (MoNx with 0≤x≤0.35) were deposited on Si(100) at room temperature using reactive DC magnetron sputtering. The residual stress of films was measured as a function of sputtering pressure, nitrogen incorporation, and annealing temperature by wafer curvature-based technique. It was found that the stress of the films was strongly related to their microstructure, which depended mainly on the incorporation of nitrogen in the films. The film stresses without nitrogen addition strongly depended on the argon pressure and changed from highly compressive to highly tensile in a relatively narrow pressure range of 0.8-1.6 Pa. For pressures exceeding ~5.3 Pa, the stress in the film was nearly zero. Cross-sectional transmission electron microscopy indicated that the compressively stressed films contained a dense microstructure without any columns, while the films having tensile stress had a very columnar microstructure. High sputtering-gas pressure conditions yielded dendritic-like film growth, resulting in complete relaxation of the residual tensile stresses. It was also found that the asdeposited film was poorly ordered in structure. When the film was heated at ~775 K, crystallization occurred and the stress of the film drastically changed from –0.75 to 1.65 GPa. The stress development mechanism may be due to volumetric shrinkage of the film during crystallization.

Characterization and Growth Mechanism of B12As2 Epitaxial Layers Grown on (1-100) 15R-SiC

2008 ◽  
Vol 1069 ◽  
Author(s):  
Hui Chen ◽  
Guan Wang ◽  
Michael Dudley ◽  
Zhou Xu ◽  
James. H. Edgar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Growth Mechanism ◽  
Heteroepitaxial Growth ◽  
High Quality ◽  
X Ray ◽  
Transmission Electron ◽  
Substrate Choice

ABSTRACTA systematic study is presented of the heteroepitaxial growth of B12As2 on m-plane 15R-SiC. In contrast to previous studies of B12As2 on other substrates, including (100) Si, (110) Si, (111) Si and (0001) 6H-SiC, single crystalline and untwinned B12As2 was achieved on m-plane 15R-SiC. Observations of IBA on m-plane (1100)15R-SiC by synchrotron white beam x-ray topography (SWBXT) and high resolution transmission electron microscopy (HRTEM) confirm the good quality of the films on the 15R-SiC substrates. The growth mechanism of IBA on m-plane 15R-SiC is discussed. This work demonstrates that m-plane 15R-SiC is potentially a good substrate choice to grow high quality B12As2 epilayers.

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