Antiferromagnetic order induced by an applied magnetic field in a high-temperature superconductor

It is reported in this paper on the thermally assisted flux flow in epitaxial YBa2Cu3O7-δ deposited by Laser ablation method on the SrTiO3 substrate. The resistivity measurements ρ (T, B) of the sample under various values of the magnetic field up to 14T in directions B∥ab-plane and B∥c-axis with a dc weak transport current density were investigated in order to determine the activation energy and then understand the vortex dynamic phenomena and therefore deduce the vortex phase diagram of this material. The apparent activation energy U0 (B) calculated using an Arrhenius relation. The measured results of the resistivity were then adjusted to the modified thermally assisted flux flow model in order to account for the temperature-field dependence of the activation energy U (T, B). The obtained values from the thermally assisted activation energy, exhibit a behavior similar to the one showed with the Arrhenius model, albeit larger than the apparent activation energy with ∼1.5 order on magnitude for both cases of the magnetic field directions. The vortex glass model was also used to obtain the vortex-glass transition temperature from the linear fitting of [d ln ρ/dT ] −1 plots. In the course of this work thanks to the resistivity measurements the upper critical magnetic field Hc2 (T), the irreversibility line Hirr (T) and the crossover field HCrossOver (T) were located. These three parameters allowed us to establish a phase diagram of the studied material where limits of each vortex phase are sketched in order to optimize its applicability as a practical high temperature superconductor used for diverse purposes.

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Measurements and Analysis of AC Losses in HTS Windings of Electrical Machine for Different Operation Modes

Applied Sciences ◽

10.3390/app11062741 ◽

2021 ◽

Vol 11 (6) ◽

pp. 2741

Author(s):

Sergey Zanegin ◽

Nikolay Ivanov ◽

Vasily Zubko ◽

Konstantin Kovalev ◽

Ivan Shishov ◽

...

Keyword(s):

Magnetic Field ◽

High Temperature ◽

High Temperature Superconductor ◽

High Temperature Superconductors ◽

Transport Current ◽

Operating Conditions ◽

Ac Losses ◽

Electrical Machine ◽

2Nd Generation ◽

Motor Mode

The article is devoted to the study of losses in devices based on high-temperature superconductors of the 2nd generation. The complexity of the devices under study increases from a single rack coil to a winding assembled from several coils, and finally to an electric machine operating in generator mode. This is the way to experimentally study the behavior of 2nd generation high temperature superconductor (2G HTS) carrying a transport current in various conditions: self-field, external DC, and AC magnetic field. Attention is also paid to the losses in the winding during its operation from the inverter, which simulates the operating conditions in the motor mode of a propulsion system.

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Magnetic Coupling in La0.7Ca0.3MnO3/YBa2Cu3O7/La0.7Ca0.3MnO3 Trilayers

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.289-292.303 ◽

2009 ◽

Vol 289-292 ◽

pp. 303-309

Author(s):

N.M. Nemes ◽

C. Visani ◽

J. Garcia-Barriocanal ◽

F.Y. Bruno ◽

Z. Sefrioui ◽

...

Keyword(s):

Magnetic Field ◽

High Temperature ◽

Carrier Density ◽

High Temperature Superconductor ◽

Hysteresis Loops ◽

Magnetic Coupling ◽

Oxygen Depletion ◽

Free Carrier ◽

Half Metallic ◽

Free Carrier Density

We report on the interplay between ferromagnetism and superconductivity in trilayers La0.7Ca0.3MnO3/YBa2Cu3O7/La0.7Ca0.3MnO3 made of half metallic manganite and high temperature superconductor cuprate. Samples with a fully oxygenated cuprate show a magnetic field interval where the magnetizations of the manganite are aligned antiparallel. A considerable magnetoresistance accompanies the switching between magnetization configurations (parallel vs. antiparallel) of the manganite moments. Suppression of the free carrier density of the cuprate which occurs upon oxygen depletion, results in deep modifications in the shape of the normal state hysteresis loops indicating that there may be a magnetic coupling mediated by free carrier density of the cuprate. This result outlines the importance of quasiparticle transmission in the interplay between ferromagnetism and superconductivity in this kind of samples.

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FEM-simulation of superconducting linear acceleration system for pellet injection

International Journal of Applied Electromagnetics and Mechanics ◽

10.3233/jae-209467 ◽

2020 ◽

Vol 64 (1-4) ◽

pp. 1469-1475

Author(s):

Teruou Takayama ◽

Takazumi Yamaguchi ◽

Ayumu Saitoh ◽

Atsushi Kamitani

Keyword(s):

Magnetic Field ◽

High Temperature ◽

Applied Magnetic Field ◽

Integration Method ◽

Fem Simulation ◽

Linear Acceleration ◽

Regularization Technique ◽

Acceleration Time ◽

Pellet Injection ◽

Improper Integrals

In order to simulate the high-temperature superconducting (HTS) linear acceleration (SLA) system for the pellet injection, the integration method of the applied magnetic field generated from the acceleration coil has been proposed. To this end, the regularization technique is used in the evaluation of the improper integrals, and simultaneously, a FEM code is developed for analyzing the shielding current density in an HTS film. In addition, the SLA system has been simulated using the code. The results of the computations show that the accuracy of the applied magnetic field is considerably improved. In this sense, the regularization technique is a useful tool. Also by locating the outer coil, the acceleration time during which the pellet speed reaches 5 km/s is about 3.5 times shorter than that of the only use of the inner coil. These results mean that the outer coil is effective in the improvement of the acceleration performance for the SLA system.

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HIGH MAGNETIC FIELD HALL EFFECT AND MAGNETORESISTANCE STUDIES OF Y-Ba-Cu-O: A HIGH Tc SUPERCONDUCTOR

International Journal of Modern Physics B ◽

10.1142/s0217979287000566 ◽

1987 ◽

Vol 01 (02) ◽

pp. 413-417

Author(s):

J.D. Hettinger ◽

A.G. Swanson ◽

J.S. Brooks ◽

Y.P. Ma

Keyword(s):

Magnetic Field ◽

High Temperature ◽

Transition Temperature ◽

Hall Effect ◽

High Temperature Superconductor ◽

Strong Dependence ◽

Zero Magnetic Field ◽

High Tc ◽

Relative Percentage ◽

High Tc Superconductor

We have measured the transition temperature, critical field, magnetoresistance, and Hall effect for the high temperature superconductor Y-Ba-Cu-O in magnetic fields up to 23T in the temperature range 4.2 to 125K. Meissner studies at zero magnetic field were also performed in some cases. We find a strong dependence of these parameters on the relative percentage of the correct phase of Y-Ba-Cu-O in the sample. We report new results on magnetoresistance and Hall effect in these materials.

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MAGNETIC HYSTERESIS OF HIGH-TEMPERATURE YBa2Cu3Ox-AgO SUPERCONDUCTORS: EXPLANATION OF MAGNETIC SUSPENSION

Modern Physics Letters B ◽

10.1142/s0217984988000618 ◽

1988 ◽

Vol 02 (07) ◽

pp. 869-874 ◽

Cited By ~ 37

Author(s):

C.Y. HUANG ◽

Y. SHAPIRA ◽

E.J. MCNIFF ◽

P.N. PETERS ◽

B.B. SCHWARTZ ◽

...

Keyword(s):

Magnetic Field ◽

High Temperature ◽

Simple Model ◽

Hysteresis Loop ◽

Applied Magnetic Field ◽

Magnetic Hysteresis ◽

Magnetic Suspension ◽

Pinning Centers ◽

Strong Pinning

We have measured the magnetization M of superconducting YBa 2 Cu 3 O x- AgO composites with T c approximately equal to 92K as a function of an applied magnetic field H at 77 and 87K. A very pronounced M-H hysteresis loop occurs even at 87K, indicating the presence of extremely strong pinning centers. The results of these measurements, together with a simple model, explain quantitatively why these superconductors could be suspended below a magnet.

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