Ba2RESbO6 (RE = Nd, Eu and Dy); Characterization and Potential Use as Substrate for Superconducting YBCO Films

1997 ◽  
Vol 11 (20) ◽  
pp. 889-897 ◽  
Author(s):  
P. R. S. Wariar ◽  
J. Kurian ◽  
P. K. Sajith ◽  
T. G. N. Babu ◽  
J. Koshy
Keyword(s):  
Single Phase ◽  
Detrimental Effect ◽  
Diffraction Measurement ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Complex Perovskite ◽  
X Ray ◽  
Dielectric Constant And Loss ◽  
Zero Resistance ◽  
Potential Use

Perovskite compounds of the general formula, Ba2RESbO6 (where RE = Nd, Eu and Dy) were sintered as single phase materials by standard solid state techniques. These compounds are found to be isostructural and to have a complex perovskite structure as observed by powder X-ray diffraction measurement. No chemical reaction between YBa2Cu3O 7-δ and Ba2RESbO6 compounds, was observed even under severe heat treatment at 950°C, and the addition of Ba2RESbO6 up to 20 vol% in YBa2Cu3O 7-δ, shows no detrimental effect on the superconducting properties of YBa2Cu3O 7-δ. The dielectric constant and loss factor values of sintered specimens, are in a range suitable for their use as substrates for microwave applications. Thick films of YBCO fabricated on highly polished Ba2RESbO6 specimens, gave a superconducting zero resistance transition T c(o) of 92 K, with a critical current density, J c of 2×104 A/cm2 at 77 K.

REBa2ZrO5.5 (RE = La, Ce, Eu, and Yb): Synthesis, characterization, and their potential use as substrates for YBa2Cu3O7–δ superconductors

1997 ◽  
Vol 12 (11) ◽  
pp. 2976-2980 ◽  
Author(s):  
R. Jose ◽  
Asha M. John ◽  
J. Kurian ◽  
P. K. Sajith ◽  
J. Koshy
Keyword(s):  
Single Phase ◽  
Detrimental Effect ◽  
Solid State Reaction Method ◽  
Dielectric Constants ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resistivity Measurements ◽  
New Class ◽  
Zero Resistance ◽  
Potential Use

A new class of complex perovskites REBa2ZrO5.5 (where RE = La, Ce, Eu, and Yb) have been synthesized and sintered as single phase materials by the solid state reaction method. The structure of these materials was studied by x-ray diffraction, and all of them were found to be isostructural, having a cubic perovskite structure. X-ray diffraction and resistivity measurements have shown that there is no detectable chemical reaction between YBa2Cu3O7–delta; and REBa2ZrO5.5 even under severe heat treatment at 950 °C, and that the addition of REBa2ZrO5.5 up to 20 vol.% in YBa2Cu3O7–δ shows no detrimental effect on the superconducting properties of YBa2Cu3O7-δ. Dielectric constants and loss factors are in the range suitable for their use as substrates for microwave applications. Thick films of YBa2Cu3O7–δ fabricated on polycrystalline REBa2ZrO5.5 substrates gave a zero resistance transition temperature Tc(0) ∼ 92 K, indicating the suitability of these materials as substrates for YBa2Cu3O7–δ.

SUPERCONDUCTING PROPERTIES OF THE HIGH Tc SUPERCONDUCTING Er-Ba-Cu-O COMPOUND

1989 ◽  
Vol 03 (03) ◽  
pp. 441-444 ◽  
Author(s):  
S. M. M. R. NAQVI ◽  
FIROZ AHMAD ◽  
JAWAID ALAM ◽  
SHARFUDDIN AHMAD
Keyword(s):  
Superconducting Phase ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray ◽  
Zero Resistance ◽  
Two Phases

Two batches of Er-Ba-Cu-O superconductors have been prepared. The zero resistance temperature is 86 K with T c onsets at 99 K and 92 K respectively. Susceptibility measurements show superconducting phase at LN 2. X-ray diffraction results indicates two phases, the superconducting being the major one.

STUDY OF Y1-xCaxBa2-yLayCu3Oz CARRIER UN-COMPENSATING SYSTEM

2009 ◽  
Vol 23 (25) ◽  
pp. 5039-5047
Author(s):  
W. T. JIN ◽  
S. J. HAO ◽  
H. ZHANG ◽  
Y. ZHAO
Keyword(s):  
Critical Temperature ◽  
Carrier Concentration ◽  
Single Phase ◽  
Magnetization Measurement ◽  
The Self ◽  
Careful Study ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Lengths

The single-phase samples of Y 0.9 Ca 0.1 Ba 2-y La y Cu 3 O z and Y1-x Ca x Ba 1.5 La 0.5 Cu 3 O z were synthesized with both x and y from 0 to 0.5, respectively. Structural and superconducting properties have been investigated by X-ray diffraction, Rietveld refinement, and DC magnetization measurement, respectively. Different from the self-compensating compound of Y 1-x Ca x Ba 2-x La x Cu 3 O z, carriers in these two systems of Y1-x Ca x Ba 2-y La y Cu 3 O z are not compensated as x ≠ y. By careful study of the chemical bond lengths related to Cu (2)– O plane and Cu (1)– O chain, it is demonstrated that the critical temperature (Tc) changes monotonously with the bond lengths of Cu (1)– O (4) and Cu (2)– O (4). The analysis demonstrates that crystalline structure is one of the important factors to high-Tc superconductivity, and its influence is independent of the carrier concentration.

SUPERCONDUCTIVITY AND STRUCTURES OF MBa2Cu3O7−x (WITH M = Y, Eu AND Yb) OXIDES

1988 ◽  
Vol 02 (06) ◽  
pp. 1407-1410 ◽  
Author(s):  
M. N. KHAN ◽  
S. Al-DALLAL ◽  
A. MEMON
Keyword(s):  
Tetragonal Phase ◽  
Perovskite Structure ◽  
Single Phase ◽  
Chemical System ◽  
Temperature Transition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ir Studies ◽  
Zero Resistance ◽  
Orthorhombic Perovskite

We have prepared and observed that the zero-resistance temperature transition occurs in the chemical system MBa 2 Cu 3 O 7 (M = Y, Eu and Yb). The highest T c (ρ = 0) is 92.50 K for Y, 93.80 K for Eu and 96.00 for Yb. The X-ray diffraction analysis shows that these compounds correspond to a single phase which is an orthorhombic perovskite structure. The results of the infrared (IR) studies on orthorhombic and tetragonal phases of some of these compounds provide evidence for the oxygen rearrangement on going from the orthorhombic to the tetragonal phase.

ANALYSIS OF FLUCTUATION CONDUCTIVITY OF GRANULAR Gd1-xPrxBa2Cu3O7-δ SUPERCONDUCTOR

2010 ◽  
Vol 24 (24) ◽  
pp. 2465-2475 ◽  
Author(s):  
CRISTIANO SANTOS LOPES ◽  
LINCOLN BRUM DE LEITE GUSMÃO PINHEIRO ◽  
MARCELO DOS SANTOS ◽  
ALCIONE ROBERTO JURELO ◽  
ROSÂNGELA MENEGOTTO COSTA ◽  
...  
Keyword(s):  
Critical Temperature ◽  
Electrical Transport ◽  
Single Phase ◽  
Transition Width ◽  
X Ray Diffraction ◽  
Solid State Reaction Technique ◽  
Fluctuation Conductivity ◽  
X Ray ◽  
Zero Resistance ◽  
Resistance State

Single phase polycrystalline Gd 1-x Pr x Ba 2 Cu 3 O 7-δ (0 ≤ x ≤ 0.10) samples have been prepared by standard solid state reaction technique and characterized by SEM, X-ray diffraction and electrical transport experiments. The samples were granular and homogeneous. It was observed that the critical temperature decreases and that the transition width increases with increasing Pr doping. Systematic measurements of fluctuation conductivity are reported. Special attention is taken above the critical temperature, where Gaussian and critical regimes are observed. Below the critical temperature, on approaching the zero resistance state, our results show a power-law behavior consistent with a phase transition from a paracoherent to a coherent state of the granular array.

SUPERCONDUCTIVITY IN THE U-Y-Ba-Cu-O SYSTEM

1987 ◽  
Vol 01 (07n08) ◽  
pp. 323-326 ◽  
Author(s):  
Q.Z. QIN ◽  
A.D. HE ◽  
W.J. JIA ◽  
L.D. MA ◽  
Z.Y. HUA
Keyword(s):  
Single Phase ◽  
Ambient Pressure ◽  
Raw Material ◽  
Material Structure ◽  
Nominal Composition ◽  
Uranium Oxides ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zero Resistance ◽  
Superconducting Oxides

High Tc superconductivity has been observed in a new U-Y-Ba-Cu-O system at ambient pressure. The zero-resistance temperature in the sample with nominal composition of U0.1Y1.1Ba0.8CuO4−δ is 87K with a width of 2K. X-ray diffraction analysis shows that none of the peaks could be fitted to the uranium oxides and the other raw material structure, and its pattern might be attributed to new multiple phases with structure different from the known single-phase superconducting oxides.

Preparation of Bi-Pb-Sr-Ca-Cu-O Superconductor By Thermal Decomposition of an Edta Colloid

1990 ◽  
Vol 180 ◽  
Author(s):  
H.S. Koo ◽  
C.K. Chiang ◽  
Y.T. Huang ◽  
G.C. Tu
Keyword(s):  
Thermal Decomposition ◽  
Solid State ◽  
Solid State Reactions ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Microstructural Characteristics ◽  
High Tc ◽  
X Ray ◽  
Metal Nitrates ◽  
Zero Resistance

ABSTRACTHigh-Tc superconducting Bi-Pb-Sr-Ca-Cu oxide with zero resistance temperature at above lOOK has been synthesized via the use of ethylenediamine-tetra-acetate(EDTA) colloid and corresponding metal nitrates. Remarkable sinterability of the precursor requires shorter time to achieve superconducting phases than conventional solid-state reactions. Superconducting properties were measured electrically and magnetically. The thermal decomposition, X-ray diffraction and microstructural characteristics of the precursor and the sintered samples were also discussed.

MÖSSBAUER EFFECT STUDY OF THE EU-Y-Ba-Cu-O SUPERCONDUCTOR

1987 ◽  
Vol 01 (02) ◽  
pp. 491-494
Author(s):  
Weiming Xu ◽  
Xiaoxiang Liu ◽  
Mingzhi Jin ◽  
Lanying He ◽  
Yifeng Wang ◽  
...  
Keyword(s):  
Isomer Shift ◽  
Mössbauer Effect ◽  
Single Phase ◽  
Hyperfine Interactions ◽  
Effect Study ◽  
X Ray Diffraction ◽  
Mossbauer Effect ◽  
X Ray ◽  
Zero Resistance ◽  
The Eu

In this work the hyperfine interactions of (EuxY1−x)0.3Ba0.1CuO3(x=0.5, 0.7, 1.0) superconductors have been studied by 151Eu Mössbauer effect. X-ray diffraction shows that the materials are of single phase. Mössbauer spectra were measured at 300K and 83K. The results show that Eu ions are in the trivalent oxidation state. The isomer shift decreases with the increasing of composition x. The electron density at the 151Eu nuclei is decreased below the zero resistance temperature.

Synthesis of single phase YBa2Cu3O7−x thin films from a Y-Ba-Cu metallic precursor by a low-temperature annealing

1994 ◽  
Vol 9 (6) ◽  
pp. 1337-1342
Author(s):  
Takashi Hase ◽  
Ryusuke Kita ◽  
Kenichi Kawaguchi ◽  
Takeshi Koga ◽  
Tadataka Morishita
Keyword(s):  
Thin Films ◽  
Single Phase ◽  
Superconducting Thin Films ◽  
Ybco Thin Film ◽  
X Ray Diffraction ◽  
Metallic Precursor ◽  
X Ray ◽  
Low Temperature Annealing ◽  
Zero Resistance ◽  
Diffraction Peaks

YBa2Cu3O7−x (YBCO) superconducting thin films that show no x-ray diffraction peaks due to any other non-superconducting phases have been synthesized by annealing Y-Ba-Cu-O amorphous precursors at 750 °C. The Y-Ba-Cu-O precursors have been fabricated by oxidizing Y-Ba-Cu metallic precursors coevaporated from Y, Ba, and Cu metallic sources under ultrahigh vacuum conditions. Crystallization behavior from the Y-Ba-Cu-O precursor to YBCO films drastically depends on an oxidation temperature for the Y-Ba-Cu metallic precursor. YBCO thin film synthesized from the precursor oxidized at an optimum temperature shows a zero resistance temperature of over 80 K and a very smooth surface.

DIRECTED REACTION PROCESS AND STRUCTURAL STUDY OF SINGLE-PHASE SUPERCONDUCTING COMPOUND YBa2Cu3O6.5+δ

1987 ◽  
Vol 01 (04) ◽  
pp. 181-186
Author(s):  
CHUNLIN JI ◽  
CHUANMENG CUI ◽  
KUIHAN WAN ◽  
SULAN LIU ◽  
GUIYI ZENG ◽  
...  
Keyword(s):  
Single Phase ◽  
Polycrystalline Material ◽  
Reaction Process ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Physico Chemical ◽  
Zero Resistance ◽  
Superconducting Compound ◽  
The Stability

A directed reaction process based on physico-chemical principles has been designed for producing single-phase 90 K “zero-resistance” superconducting compound YBa2Cu3O6.5+δ. The reliability of the process has been well proved by the stability and reproducibility of results in resistance and AC magnetic susceptibility measurements of seven samples taken randomly from three batches of products. X-ray diffraction, SEM and TEM examinations have identified the product as single-phase polycrystalline material of orthorhombic structure with lattice parameters a=3.89 Å, b=3.82 Å and c=11.65 Å. Many micro-twinned defects were observed under TEM along [110] axes. The nonstoichiometric fraction, δ value, was determined using a physico-chemical method.

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