Processing of Superconducting Ceramics Using Microwave Energy

1988 ◽  
Vol 124 ◽  
Author(s):  
Iftikhar Ahmad ◽  
G. T. Chandler ◽  
D. E. Clark
Keyword(s):  
Oxygen Content ◽  
Annealed Sample ◽  
Microwave Energy ◽  
Superconducting Properties ◽  
Internal Heating ◽  
Heating Mechanism ◽  
Refined Microstructure ◽  
Superconducting Ceramics

ABSTRACTSuperconducting ceramics have been successfully prepared employing a novel internal heating mechanism which uses microwave energy. Calcining with microwaves requires further investigation to improve the superconducting properties. Sintering and annealing in microwave energy shows refined microstructure and improved oxygen content in the YBa2Cu3O7-x phase. This is attributed to the coupling of CuO with microwave energy. The onset of the superconductive transition occurs at 93°K for the conventionally calcined/microwave annealed samples. The conventionally processed samples have an onset transition at 90°K and exhibit weaker diamagnetism when compared with the microwave annealed sample.

Dielectric Relaxation Process and Microwave Heating Mechanism in ε-Caprolactone as a Function of Frequency and Temperature

2014 ◽  
Vol 931-932 ◽  
pp. 205-209 ◽  
Author(s):  
Mohd Johari Kamaruddin ◽  
Anwar Johari ◽  
Ramli Mat ◽  
Tuan Amran Tuan Abdullah ◽  
Siti Hamidah Mohd Setapar ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Microwave Heating ◽  
Processing System ◽  
Debye Model ◽  
Microwave Energy ◽  
Dielectric Relaxation Process ◽  
Microwave Assisted ◽  
Heating Mechanism ◽  
Wide Range ◽  
Properties Of Materials

Dielectric properties of materials play a significant role in design of microwave assisted processing system. This paper is focused on the dielectric properties of ε-caprolactone (ε-cap) which is the monomer for the biodegradable polymer, Poly (ε-caprolactone) (PCL). The dielectric properties of ε-cap were measured across a wide range of frequencies (0.1 GHz5.0 GHz) and temperatures (20-150oC). Then the measured dielectric properties data was modelled using Debye model in order to relate quantitatively the dielectric properties to microwave heating mechanisms. The analysis carried out gives a clear picture of interaction of ε-cap with microwave energy and its heating mechanism in microwave assisted polymerisation process. This study concluded that microwave heating mechanism of the ε-cap in the measured range may be dominated by the dipole reorientation.

Y-BA-CU-O SUPERCONDUCTING CERAMICS

1987 ◽  
Vol 01 (05n06) ◽  
pp. 255-258
Author(s):  
SHUNBAO TIAN ◽  
XIAOFEI LI ◽  
TINGLIAN WEN ◽  
ZUXIANG LIN ◽  
SHICHUN LI ◽  
...  
Keyword(s):  
Grain Size ◽  
Chemical Composition ◽  
Processing Condition ◽  
Superconducting Materials ◽  
Structure Model ◽  
Superconducting Properties ◽  
Final Structure ◽  
Superconducting Ceramics

Polycrystalline Y-Ba-Cu-O superconducting materials have been studied. It was found that chemical composition and processing condition may play an important role in the final structure and superconducting properties. The density has been determined and compared with the calculated value according to the structure model reported by Bell Labs. The grain size and the morphology of the materials were observed by SEM.

Comparing the effects of oxygen content on the superconducting properties of YBa2Cu3Ox and RBa2Cu3Ox with R=Nd, Eu and Gd

1999 ◽  
Vol 317-318 ◽  
pp. 624-626 ◽  
Author(s):  
S. Glenis ◽  
T. Yuen ◽  
C.L. Lin ◽  
J.A. Zan ◽  
T. Mihalisin
Keyword(s):  
Oxygen Content ◽  
Superconducting Properties

A Hydroxycarbonate Route to Superconductor Precursor Powders

1987 ◽  
Vol 99 ◽  
Author(s):  
J. A. Voigt ◽  
B. C. Bunker ◽  
D. H. Doughty ◽  
D. L. Lamppa ◽  
K. M. Kimball
Keyword(s):  
Critical Temperature ◽  
Structural Integrity ◽  
Nitrate Solution ◽  
High Density ◽  
Tetramethylammonium Hydroxide ◽  
Precipitation Process ◽  
High Critical Temperature ◽  
Superconducting Properties ◽  
Superconducting Ceramics ◽  
Precursor Powders

ABSTRACTA precipitation process is described for the preparation of powders that can be thermally decomposed to form high critical temperature superconductors such as YBa2Cu3O7. In the process, a cationic solution (a concentrated chloride or nitrate solution) is instantaneously mixed with an anionie solution (a mixture of tetramethylammonium hydroxide and carbonate) to produce a metal-hydroxycarbonate precipitate having the metal stoichiometry of the desired superconducting oxide. The calcining and sintering of the precipitates is critical in controlling the structural integrity and morphology of the superconducting ceramics made from the chem-prep powders, as well as controlling superconducting properties. Under appropriate conditions, high density (>95%) materials that exhibit good superconducting characteristics can be prepared with the chem-prep powders.

Effects of oxygen content on the superconducting properties of melt-textured LRE123 superconductors

1997 ◽  
Vol 278 (3-4) ◽  
pp. 187-191 ◽  
Author(s):  
N. Chikumoto ◽  
S. Ozawa ◽  
S.I. Yoo ◽  
N. Hayashi ◽  
M. Murakami
Keyword(s):  
Oxygen Content ◽  
Superconducting Properties

scholarly journals PROBLEMS OF COEXISTENCE OF SUPERCONDUCTIVITY AND MAGNETIC ORDERING OF COPPER SUBLATTICES IN YBa2Cu3-XFeXO7-X CERAMICS

2020 ◽  
Vol 1 ◽  
pp. 57-62
Author(s):  
M Ruzieva ◽  
Q Bobomurodov ◽  
S Bobomurodov ◽  
R Shokirov
Keyword(s):  
Solid Solution ◽  
Mössbauer Spectroscopy ◽  
Transition Temperature ◽  
Oxygen Content ◽  
Superconducting State ◽  
Mossbauer Spectroscopy ◽  
Magnetic Ordering ◽  
Orthorhombic Lattice ◽  
Antiferromagnetic Ordering ◽  
Superconducting Ceramics

The article studies the problems of coexistence of superconductivity and magnetic ordering of copper sublattices in YBa2Cu3-xFexO7-x ceramics. It is known that in superconducting ceramics YBa2Cu3O7-z with orthorhombic lattice as the oxygen content decreases, the transition temperature in superconducting state Tc decreases, and at z>0.6 superconductivity disappears, the lattice becomes tetragonal and at the same time, antiferromagnetic ordering of sublattices Cu (2) appears. The substitution in ceramics of YBa2Cu3O7 part of copper atoms by iron atoms (i.e., the formation of a solid solution of YBa2Cu3-xFexO7+y) is accompanied by similar effects: as x increases, Tc decreases, at x>0.05 the orthorhombic lattice becomes tetragonal, at x>0.45 the superconductivity disappears. The most significant moment is the fact of coexistence in ceramics YBa2Cu3-xFexO7+y in the region of compositions 0.03 < x < 0.45 of superconductivity and magnetic ordering of iron atoms in copper nodes (the latter is established by Mossbauer spectroscopy on isotope 57Fe in a large number of works. However, it remains unclear whether the magnetic ordering of iron atoms in the YBa2Cu3-xFexO7+y lattice is related to the magnetic ordering of copper atoms

Effect of Oxygen Content on the Superconducting Properties of Nd1+xBa2-xCu3O7-δ (x=0.0, 0.1, 0.2, 0.3, and 0.4)

1998 ◽  
pp. 573-576
Author(s):  
Shinobu Ozawa ◽  
Noriko Chikumoto ◽  
Goro Osabe ◽  
Masato Murakami ◽  
Masahisa Ohtsuka
Keyword(s):  
Oxygen Content ◽  
Superconducting Properties ◽  
Effect Of Oxygen

Variation of the superconducting properties of Bi2Sr2CaCu2O8+x with oxygen content

1991 ◽  
Vol 176 (1-3) ◽  
pp. 247-256 ◽  
Author(s):  
G. Triscone ◽  
J.-Y. Genoud ◽  
T. Graf ◽  
A. Junod ◽  
J. Muller
Keyword(s):  
Oxygen Content ◽  
Superconducting Properties

SUPERCONDUCTING PROPERTIES OF Sn ADDED (BiPb)2Sr2Ca1Cu2Oy

1992 ◽  
Vol 06 (18) ◽  
pp. 3079-3086 ◽  
Author(s):  
B. R. SEKHAR ◽  
P. SRIVASTAVA ◽  
K. ASOKAN ◽  
N. L. SAINI ◽  
K. B. GARG
Keyword(s):  
Oxygen Content ◽  
Superconducting Properties

The addition of Sn in two layered bismuthate superconductors has been investigated using EDAX and SEM. The addition of Sn was found to enhance Tc from 88 K( Sn =0) to 95 K ( Sn =0.3). The possible increase in oxygen content may be the reason for the increase in Tc.

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