The Frequency Dependence of the AC Susceptibility in High-Tc Ceramic Superconductors

1994 ◽  
Vol 184 (1) ◽  
pp. K15-K17 ◽  
Author(s):  
Z. D. Wang ◽  
P. C. W. Fung
Keyword(s):  
Frequency Dependence ◽  
Ac Susceptibility ◽  
High Tc ◽  
Ceramic Superconductors

The Nature of Flux Pinning in High TC Ceramic Superconductors / Die Wirkungsweise der Flußschlauch-Haftung in Keramik-Hochtemperatur-Supraleitern

1988 ◽  
Vol 79 (5) ◽  
pp. 271-277
Author(s):  
Chalakara V. Narasimha Rao ◽  
Shyam K. Agarwal ◽  
Betanabhatla Jayaram ◽  
Sylvester Takacs ◽  
Anant V. Narlikar
Keyword(s):  
Flux Pinning ◽  
High Tc ◽  
Ceramic Superconductors

Field induced transition of the AC susceptibility in high-Tc superconductors

1996 ◽  
Vol 46 (S3) ◽  
pp. 1589-1590 ◽  
Author(s):  
Oliver Waldmann ◽  
Gerald Lichtschlag ◽  
Florian Steinmeyer ◽  
Andrei Talalaevskii ◽  
Paul Müller
Keyword(s):  
Ac Susceptibility ◽  
High Tc Superconductors ◽  
High Tc

The Frequency Dependence of AC Susceptibility for Bi-2223/Ag Tapes With Varying Lengths

2019 ◽  
Vol 29 (2) ◽  
pp. 1-4
Author(s):  
Yueming Sun ◽  
Xinyu Fang ◽  
Jin Fang ◽  
Duxing Chen ◽  
Shuo li ◽  
...  
Keyword(s):  
Frequency Dependence ◽  
Ac Susceptibility

A STRUCTURAL CHEMICAL MODEL FOR HIGH Tc CERAMIC SUPERCONDUCTORS

1987 ◽  
Vol 01 (07n08) ◽  
pp. 275-288 ◽  
Author(s):  
S.R. OVSHINSKY ◽  
S.J. HUDGENS ◽  
R.L. LINTVEDT ◽  
D.B. RORABACHER
Keyword(s):  
Electronic Properties ◽  
Oxygen Vacancies ◽  
Oxygen Removal ◽  
Bose Condensation ◽  
Oxidation States ◽  
Chemical Model ◽  
Electrically Conductive ◽  
High Tc ◽  
Ceramic Superconductors ◽  
Mixed Oxidation

A structual chemical model for high Tc ceramic superconductors is proposed in which carriers pairs, coupled through a superexchange process, undergo Bose condensation. In the Y-Ba-Cu-O system, Cu atoms on “chain” sites and “sheet” sites are initially assigned formal oxidation states of +3 and +2, respectively, and “sheet”/“chain” interactions are then introduced to bring about the electrically conductive mixed oxidation state. This model explains the presence of labile oxygen in the “chain” structures, describes the structure of deoxygenated phases exhibiting ordered oxygen vacancies in the “chains”, and allows interpretation of the effects of oxygen removal on magnetic and electronic properties of the material.

High-Tc Ceramic Superconductors Through Oxidation of Mechanically Alloyed Y-Ba-Cu and Bi-Sr-Ca-Cu Powders

1989 ◽  
pp. 281-286
Author(s):  
Shin-ichi Murasaki ◽  
Satoru Taniguchi ◽  
Uichiro Mizutani ◽  
Motohiro Suganuma ◽  
Yuh Yamada
Keyword(s):  
Mechanically Alloyed ◽  
High Tc ◽  
Ceramic Superconductors

A Device for Measuring High-TC Superconductor Transition Temperature with Electric Transport and AC Susceptibility Methods Based on Small Cryocooler Cooling

2013 ◽  
Vol 745-746 ◽  
pp. 152-157 ◽  
Author(s):  
San Sheng Wang ◽  
Xiao Shuai Ning ◽  
Xiang Hua Chu ◽  
Hua Li
Keyword(s):  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Ac Susceptibility ◽  
Transition Curve ◽  
Secondary Coil ◽  
Electric Transport ◽  
Superconducting Transition ◽  
High Tc ◽  
High Tc Superconductor ◽  
Lock In

A device for measuring high-TC superconducting transition temperature in a small cryocooler is described which allows a samples temperature to fall steadily from room temperature to 45K. This cryocooler not only meets the high-TC superconductors measurement requirements, but also yields accurate measurement results under ambient conditions. In this device, two measurement methods for measuring high-TC superconducting transition temperature are applied: the electric transport and the AC susceptibility. The former adopts a four-wire method to eliminate the contact resistance between the leads and the sample. During the measurement process the current reversal method for datum processing is applied to eliminate the thermoelectric voltages; this ensures the repeatability error less than 0.4K in the measurement of the superconducting transition temperature. The AC susceptibility method adopts a lock-in amplifier to provide an AC voltage signal for the primary coil, and then lock-in amplifier is used to measure the electrical signals of the secondary coil according to the AC magnetic susceptibility values. The advantage of this device is that by merely changing the position of the sample in the vacuum chamber, the R-T curve and the χ-T curve of a superconducting sample in the same temperature range can be automatically recorded, which provides reliable data for high-TC superconductor transition curve measurement.

Ac Susceptibility Studies of the High Tc Superconductors: Dissipative Effects in La2.xSrxCuO4-Y and YBa2Cu3O7-Y Systems

1989 ◽  
Vol 169 ◽  
Author(s):  
Xinsheng Ling ◽  
M. E. Filipkowski ◽  
E. K. Heller ◽  
J. I. Budnick
Keyword(s):  
Grain Boundaries ◽  
Order Parameter ◽  
Ac Susceptibility ◽  
Similar Process ◽  
Charge Carrier Density ◽  
High Tc Superconductors ◽  
High Tc ◽  
Spatial Fluctuation ◽  
Dissipative Effects ◽  
Ceramic Samples

AbstractWe have studied the variation of dissipative effects with doping in the high Tc superconductors La2-xSrxCuO4-y and YBa2Cu3O7-y by studying the lossy component of ac susceptibility as a function of temperature. We find relatively strong excess losses at low temperature in both systems, which indicate stronger flux creep at grain boundaries, in lower level doped ceramic samples produced by a similar process. This effect is more significant in the La2-xSrxCuO4-y (214) system than in the YBa2Cu3O7-y(123) system. We suggest that the microscopic mechanisms of weakening of the order parameter in the grain boundaries may be different in the two systems. In the 214 system, as the charge carrier density in the CuO2 planes is reduced, the spatial fluctuation of the order parameter in the CuO2 planes is enhanced. In the 123 system, the initial removal of O from the sample, which weakens the coupling between planes and increases the spatial fluctuation of the order parameter between CuO2 planes. The grain boundaries are degraded in both systems. The degradation in the 214 samples is more significant than in the 123 samples.

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