scholarly journals Cross-sectional Area Dependence of Tunnel Magnetoresistance, Thermal Stability and Critical Current Density in MTJ

2020 ◽  
pp. 1-1
Author(s):  
Aijaz H. Lone ◽  
Shivangi Shringi ◽  
Kishan Mishra ◽  
Srikant Srinivasan
Keyword(s):  
Thermal Stability ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Tunnel Magnetoresistance

Thickness dependence of microstructure and critical current density of Yba2Cu3O7−δ on rolling-assisted biaxially textured substrates

2003 ◽  
Vol 18 (5) ◽  
pp. 1109-1122 ◽  
Author(s):  
K. J. Leonard ◽  
A. Goyal ◽  
D. M. Kroeger ◽  
J. W. Jones ◽  
S. Kang ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Ybco Film ◽  
Cube Texture ◽  
Film Surface ◽  
Second Phase ◽  
Film Properties ◽  
Cross Sectional ◽  
Ybco Films

The change in microstructure associated with the decrease in critical current density (Jc) of Yba2Cu3O7−δ (YBCO) films with increasing thickness was examined. Samples of pulse laser deposited YBCO films varying in thickness from 0.19 to 3.0 μm on rolling-assisted biaxially textured substrates with an architecture of CeO2/YSZ/CeO2/Ni were prepared by tripod polishing for cross-sectional electron microscopy. More randomly oriented grains in the upper portion of the YBCO film surface were observed with increasing film thickness, resulting in less cube texture. In addition, increases in mismatch across the boundaries of the c-axis grains with increasing time during deposition, along with the development of BaCeO3 and Y2BaCuO5 phases at the YBCO/CeO2 interface, contributed to the degradation of film properties. Surface outgrowths of the YBCO film were examined as well as the defect structures and second-phase formations within the films.

Critical Current Density and Microstructure of Yba2Cu3O7-X Films as a Function of Film Thickness

1989 ◽  
Vol 169 ◽  
Author(s):  
A. Mogro-Campero ◽  
L.G. Turner ◽  
E.L. Hall ◽  
N. Lewis
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Film Plane ◽  
Nominal Composition ◽  
Substrate Plane ◽  
Furnace Annealing ◽  
Cross Sectional ◽  
Continuous Layer ◽  
Transmission Electron

AbstractThin films of nominal composition YBa2Cu3O7‐x (YBCO) were produced on (100) SrTiO3 substrates by coevaporation and furnace annealing. Film thicknesses in the range of 0.2 to 2.4/μm were analyzed. Microstructural investigations by cross sectional transmission electron microscopy (TEM) reveal a continuous layer of about 0.4 μm thickness adjacent to the substrate with c‐axis normal to the substrate plane. In thicker films the remaining top portion has the c‐axis in the film plane. The critical current density (J ) at 77 K decreases with increasing thickness in the thickness range exceeding 0.4 μm, qualitatively consistent with the microstructural observations, but quantitatively inconsistent with a simple model based on the microstructural data.

HREM of Epitaxial YBa2Cu3O7 Thin Films

1990 ◽  
Vol 183 ◽  
Author(s):  
T. E. Mitchell ◽  
S. N. Basu ◽  
M. Nastasi ◽  
T. Roy
Keyword(s):  
Thin Films ◽  
Critical Current Density ◽  
Grain Boundaries ◽  
Critical Current ◽  
Current Density ◽  
Small Angle ◽  
Stacking Faults ◽  
Cross Sectional ◽  
Relationship Of ◽  
The Relationship

AbstractThin films of YBa2Cu3O7 have been prepared by evaporation of Cu, Y and BaF2 onto (001) SrTiO3, LaGaO3. and LaAlO3 and subsequent annealing. Their microstructures have been examined by HREM of cross-sectional specimens. Epitaxial (001) grains of YBa2Cu3O7 form near the substrate interface in thin films but (001) and (010) grains tend to nucleate as the film thickens. 90° grain boundaries are therefore common, as well as other defects such as small-angle boundaries, dislocations and stacking faults. HREM of the substrate/superconductor interface indicates regions of perfect epitaxy, highly distorted areas, amorphous regions and areas showing evidence of interdiffusion. The relationship of these microstructural features to critical current density is discussed.

Microstructural characterization of YBa2Cu3O7-x thin films formed by metalorganic CVD

1991 ◽  
Vol 49 ◽  
pp. 1080-1081
Author(s):  
P. Lu ◽  
W. Huang ◽  
C.S. Chern ◽  
Y.Q. Li ◽  
J. Zhao ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Film Growth ◽  
Chemical Vapor ◽  
Microstructural Characterization ◽  
Ion Milling ◽  
Conventional Grinding

The YBa2Cu3O7-x thin films formed by metalorganic chemical vapor deposition(MOCVD) have been reported to have excellent superconducting properties including a sharp zero resistance transition temperature (Tc) of 89 K and a high critical current density of 2.3x106 A/cm2 or higher. The origin of the high critical current in the thin film compared to bulk materials is attributed to its structural properties such as orientation, grain boundaries and defects on the scale of the coherent length. In this report, we present microstructural aspects of the thin films deposited on the (100) LaAlO3 substrate, which process the highest critical current density.Details of the thin film growth process have been reported elsewhere. The thin films were examined in both planar and cross-section view by electron microscopy. TEM sample preparation was carried out using conventional grinding, dimpling and ion milling techniques. Special care was taken to avoid exposure of the thin films to water during the preparation processes.

Facet Topography and Dislocation Structure as a Possible Source for Electrical Heterogeneity in [001] TILT Bicrystals of YBa2Cu3O7-δ

1996 ◽  
Vol 54 ◽  
pp. 338-339
Author(s):  
I-Fei Tsu ◽  
D.L. Kaiser ◽  
S.E. Babcock
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Electromagnetic Properties ◽  
Length Scale ◽  
Density Values ◽  
Current Densities ◽  
Applied Fields ◽  
A Current

A current theme in the study of the critical current density behavior of YBa2Cu3O7-δ (YBCO) grain boundaries is that their electromagnetic properties are heterogeneous on various length scales ranging from 10s of microns to ˜ 1 Å. Recently, combined electromagnetic and TEM studies on four flux-grown bicrystals have demonstrated a direct correlation between the length scale of the boundaries’ saw-tooth facet configurations and the apparent length scale of the electrical heterogeneity. In that work, enhanced critical current densities are observed at applied fields where the facet period is commensurate with the spacing of the Abrikosov flux vortices which must be pinned if higher critical current density values are recorded. To understand the microstructural origin of the flux pinning, the grain boundary topography and grain boundary dislocation (GBD) network structure of [001] tilt YBCO bicrystals were studied by TEM and HRTEM.

Pelvic Canal Narrowing Caused by Triple Pelvic Osteotomy in the Dog

1994 ◽  
Vol 07 (03) ◽  
pp. 110-113 ◽  
Author(s):  
D. L. Holmberg ◽  
M. B. Hurtig ◽  
H. R. Sukhiani
Keyword(s):  
Postoperative Complications ◽  
Pelvic Osteotomy ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Canal Width ◽  
Operative Complications ◽  
Post Operative Complications

SummaryDuring a triple pelvic osteotomy, rotation of the free acetabular segment causes the pubic remnant on the acetabulum to rotate into the pelvic canal. The resulting narrowing may cause complications by impingement on the organs within the pelvic canal. Triple pelvic osteotomies were performed on ten cadaver pelves with pubic remnants equal to 0, 25, and 50% of the hemi-pubic length and angles of acetabular rotation of 20, 30, and 40 degrees. All combinations of pubic remnant lengths and angles of acetabular rotation caused a significant reduction in pelvic canal-width and cross-sectional area, when compared to the inact pelvis. Zero, 25, and 50% pubic remnants result in 15, 35, and 50% reductions in pelvic canal width respectively. Overrotation of the acetabulum should be avoided and the pubic remnant on the acetabular segment should be minimized to reduce postoperative complications due to pelvic canal narrowing.When performing triple pelvic osteotomies, the length of the pubic remnant on the acetabular segment and the angle of acetabular rotation both significantly narrow the pelvic canal. To reduce post-operative complications, due to narrowing of the pelvic canal, overrotation of the acetabulum should be avoided and the length of the pubic remnant should be minimized.

DETERMINATION OF THE FUNCTION OF THE ROD’S CROSS-SECTIONAL AREA USING VIBRATION EIGENFREQUENCIES

2020 ◽  
Vol 0 (4) ◽  
pp. 19-24
Author(s):  
I.M. UTYASHEV ◽  
◽  
A.A. AITBAEVA ◽  
A.A. YULMUKHAMETOV ◽  
◽  
...  
Keyword(s):  
Cross Sectional Area ◽  
Variable Cross ◽  
Sectional Area ◽  
Longitudinal Vibrations ◽  
Cross Sectional ◽  
Method Error ◽  
Various Boundary Conditions ◽  
Elastic Fixation ◽  
Crosssectional Area

The paper presents solutions to the direct and inverse problems on longitudinal vibrations of a rod with a variable cross-sectional area. The law of variation of the cross-sectional area is modeled as an exponential function of a polynomial of degree n . The method for reconstructing this function is based on representing the fundamental system of solutions of the direct problem in the form of a Maclaurin series in the variables x and λ. Examples of solutions for various section functions and various boundary conditions are given. It is shown that to recover n unknown coefficients of a polynomial, n eigenvalues are required, and the solution is dual. An unambiguous solution was obtained only for the case of elastic fixation at one of the rod’s ends. The numerical estimation of the method error was made using input data noise. It is shown that the error in finding the variable crosssectional area is less than 1% with the error in the eigenvalues of longitudinal vibrations not exceeding 0.0001.

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