Effect of structural changes on the zero-resistance transition temperature ofLa1Ba2Cu3O9−δ

1987 ◽  
Vol 36 (4) ◽  
pp. 2417-2420 ◽  
Author(s):  
Sung-Ik Lee ◽  
John P. Golben ◽  
Sang Young Lee ◽  
Xiao-Dong Chen ◽  
Yi Song ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Structural Changes ◽  
Zero Resistance

COMPOSITION DEPENDENCE OF SUPERCONDUCTIVITY AND CRYSTAL STRUCTURE IN La(Ba1−xCax)2Cu3O7−y SYSTEM

1989 ◽  
Vol 03 (04) ◽  
pp. 307-311 ◽  
Author(s):  
N. CAO ◽  
J.Q. ZHENG ◽  
X.Y. SHAO ◽  
X.S. CHEN ◽  
W.Y. GUAN
Keyword(s):  
Crystal Structure ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Composition Dependence ◽  
Superconducting Transition ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resistivity Measurements ◽  
Zero Resistance

The composition dependence of superconductivity and crystal structure in La ( Ba 1−x Ca x)2 Cu 3 O 7−y system was determined by the resistivity measurements and X-ray diffraction analysis. The superconducting transition temperature is raised with the increase of Ca content till x=0.6, at which the zero resistance temperature of the sample is 81.5 K. In the meanwhile, the crystal structure of the sample changed from tetragonal (x=0) to orthorhombic structure (x=0.2, 0.4, 0.6). With further increase of Ca content, the superconductivity decrease for the sample of x=0.8 with mixed phases including the orthorhombic oxygen-deficient perovskite-like (ODP) structure and no superconducting transition is found at 4.2 K for the sample of x=1 without the ODP structure. A possible explanation of these experimental results is given.

SUPPRESSION OF SUPERCONDUCTIVITY AND STRUCTURAL CHANGES IN R1-xPrxBa2Cu3O7-y (R=Sm, Gd, Er, Tm, Y)

1992 ◽  
Vol 06 (16n17) ◽  
pp. 1069-1074 ◽  
Author(s):  
P. LIU ◽  
W. J. ZHU ◽  
J. L. ZHANG ◽  
S. Q. GUO ◽  
S. L. JIA ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Cell Volume ◽  
Superconducting Transition Temperature ◽  
Unit Cell Volume ◽  
Structural Changes ◽  
Unit Cell ◽  
Superconducting Transition ◽  
Lattice Constants

The compounds R 1-x Pr x Ba 2 Cu 3 O 7-y ( R = Sm , Gd , Er , Tm and Y ) have been prepared and examined for superconductivity and structural changes. It is observed that the superconducting transition temperature Tc of R 1-x Pr x Ba 2 Cu 3 O 7-y decreases monotonically with increasing Pr concentration for all systems. At constant Pr concentration, Tc decreases approximately linearly with increasing radius with R cations while the lattice constants a,b,c and unit cell volume V increase. The correlation of both the Tc and the lattice constants with the radius of R cations is the same as for 1:2:4, 2:4:7, and 1:2:1:2 compounds.

In-Situ Laser Processing and Microstructural Characteristics of YBa2Cu3O7−δ Thin Films on Si with TiN Buffer Layer

1992 ◽  
Vol 285 ◽  
Author(s):  
P. Tiwari ◽  
T. Zheleva ◽  
J. Narayan
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transition Temperature ◽  
Buffer Layer ◽  
Processing Parameters ◽  
Superconducting Transition ◽  
Epitaxial Relationship ◽  
Ybco Thin Films ◽  
Zero Resistance

ABSTRACTWe have prepared high-quality superconducting YBa2Cu3O7−δ (YBCO) thin films on Si(100) with TiN as a buffer layer using in-situ multitarget deposition system. Both TiN and YBCO thin films were deposited sequentially by KrF excitner laser ( λ = 248 nm ) at substrate temperature of 650°C. Thin films were characterized using X-ray diffraction (XRD), four-point-probe ac resistivity, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Rutherford backscattering (RBS). The TiN buffer layer was epitaxial and the epitaxial relationship was found to be cube on cube with <100> TiN // <100> Si. YBCO thin films on Si with TiN buffer layer showed the transition temperature of 90–92K with Tco (zero resistance temperature) of ∼84K. We have found that the quality of the buffer layer is very important in determining the superconducting transition temperature of the thin film. The effects of processing parameters and the correlation of microstructural features with superconducting properties are discussed indetail.

Properties and Structures of Copper Rich Y-Ba-Cu-O Superconductors

1987 ◽  
Vol 99 ◽  
Author(s):  
A. J. Drehman ◽  
J. A. Horrigan ◽  
M. W. Dumais
Keyword(s):  
Transition Temperature ◽  
Grain Boundaries ◽  
Superconducting Transition Temperature ◽  
Superconducting Transition ◽  
Zero Resistance ◽  
Resultant Material

ABSTRACTCopper rich Y-Ba-Cu-O samples were prepared by reacting and sintering powders. The resultant material is composed of YBa2Cu3Oy and CuO. Proper processing results in a 85% dense, well interconnected material with a superconducting transition temperature of 92K. Zero resistance is observed even though a quarter of the volume is the CuO phase. This is because the CuO phase is in the form of isolated grains and not at the grain boundaries of the superconducting matrix.

Preparation of superconducting HgBa2CaCu2Ox films with a zero-resistance transition temperature of 121 K

1997 ◽  
Vol 276 (3-4) ◽  
pp. 277-280 ◽  
Author(s):  
J.D. Guo ◽  
G.C. Xiong ◽  
D.P. Yu ◽  
Q.R. Feng ◽  
X.L. Xu ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Zero Resistance

Thermo-mechanical properties and thermal conductivity of CdS-trans-polyisoprene, polymer nanocomposite

2011 ◽  
Vol 31 (2-3) ◽  
Author(s):  
Mahesh Baboo ◽  
Manasvi Dixit ◽  
Dinesh Patidar ◽  
Kananbala Sharma ◽  
Narendra Sahai Saxena
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Storage Modulus ◽  
Structural Changes ◽  
Polymer Nanocomposite ◽  
Cds Nanoparticles ◽  
Chemical Route

Abstract This paper focuses on the comparative evaluation of the glass transition temperature (Tg), storage modulus and thermal conductivity of trans-polyisoprene (TPI) and CdS-TPI nanocomposite. The CdS nanoparticles synthesized by chemical route are dispersed into TPI using ultrasonic vibrations. Particle size of nanocrystals is obtained from X-ray diffraction and found to be 1.84 nm. Thermo-mechanical properties (Tg and storage modulus) are measured by dynamic mechanical analyzer (DMA), while thermal conductivity is a measured using the transient plane source (TPS) technique. It is observed that glass transition temperature and thermal conductivity are higher while storage modulus and mechanical properties are lower for CdS-TPI nanocomposites than for pure TPI. This has been explained on the basis of structural changes occurring due to introduction of CdS as filler into the TPI.

EFFECTS OF PLASMA OXIDATION ON TRANSPORT PROPERTIES OF SPUTTERED Y-Ba-Cu-O FILMS

1989 ◽  
Vol 03 (01) ◽  
pp. 87-92
Author(s):  
T. NOJIMA ◽  
S. AWAJI ◽  
Y. MAENO ◽  
T. FUJITA
Keyword(s):  
Transition Temperature ◽  
Transport Properties ◽  
Superconducting Transition Temperature ◽  
Superconducting Transition ◽  
Plasma Oxidation ◽  
Normal Resistance ◽  
Before And After ◽  
Zero Resistance

Effects of plasma oxidation on superconducting and normal properties were studied for rf-sputtered Y-Ba-Cu-O films. The plasma oxidation was performed in a mixture gas of Ar-50%O 2 both before and after annealing. The oxidation enhances superconducting transition temperature, T c , and improves metal-like behavior of normal resistance as well. Typical films obtained after the oxidation exhibited the transition with an onset at 94 K and with zero resistance below 82 K. The improvement was found to hold for more than 30 days after oxidation.

Ultrasonic Properties of a Ti47.4Zr5.3Ni5.3Cu42 Glassy Alloy during Progressive Devitrification

2007 ◽  
Vol 561-565 ◽  
pp. 1371-1374 ◽  
Author(s):  
Ichiro Seki ◽  
Mikio Fukuhara ◽  
Akihisa Inoue
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Structural Relaxation ◽  
Structural Changes ◽  
Poisson Ratio ◽  
Glassy Alloy ◽  
Acoustic Characteristics ◽  
Ultrasonic Properties ◽  
Devitrification Process

Although a Ti47.4Zr5.3Ni5.3Cu42 glassy alloy does not occur precipitation of crystalline in annealing of prolonged time below glass transition temperature, it shows slightly embrittlement during passing through devitrification process. The embrittlment behavior may be connected to structural relaxation. Using ultrasonic, in this study, acoustic characteristics of the glassy alloy during progressive devitrification were examined in terms of structural relaxation. The structural changes are characterized by decreases in specific volume, bulk modulus, Lamè parameter and Poisson ratio, accompanied by structural relaxation.

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