Penetration of a magnetic field into the YBa2Cu3O7−δ high-temperature superconductor: Magnetoresistance in weak magnetic fields

The magnetic alignment of cellulose nanocrystals (CNC) and lepidocrocite nanorods (LpN), pristine and in hybrid suspensions has been investigated using contrast-matched small-angle neutron scattering (SANS) under in situ magnetic fields (0 – 6.8 T) and polarized optical microscopy. The pristine CNC (diamagnetic) and pristine LpN (paramagnetic) align perpendicular and parallel to the direction of field, respectively. The alignment of both the nanoparticles in their hybrid suspensions depends on the relative amount of the two components (CNC and LpN) and strength of the applied magnetic field. In the presence of 10 wt% LpN and fields < 1.0 T, the CNC align parallel to the field. In the hybrid containing lower amount of LpN (1 wt%), the ordering of CNC is partially frustrated in all range of magnetic field. At the same time, the LpN shows both perpendicular and parallel orientation, in the presence of CNC. This study highlights that the natural perpendicular ordering of CNC can be switched to parallel by weak magnetic fields and the incorporation of paramagnetic nanoparticle as LpN, as well it gives a method to influence the orientation of LpN.<br>

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Sensitivity of PS/CoPd Janus particles to an external magnetic field

RSC Advances ◽

10.1039/d1ra02410h ◽

2021 ◽

Vol 11 (28) ◽

pp. 17051-17057

Author(s):

Anna Eichler-Volf ◽

Yara Alsaadawi ◽

Fernando Vazquez Luna ◽

Qaiser Ali Khan ◽

Simon Stierle ◽

...

Keyword(s):

Magnetic Field ◽

Magnetic Properties ◽

External Magnetic Field ◽

Magnetic Fields ◽

Janus Particles ◽

Weak Magnetic Fields

PS/CoPd Janus particles respond very sensitively to application of low external magnetic fields. Owing to the magnetic properties, the PS/CoPd particles may be used, for example, to sense the presence of weak magnetic fields as micro-magnetometers.

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The activation energy U(T,B) in high temperature superconductor

The European Physical Journal Applied Physics ◽

10.1051/epjap/2020200223 ◽

2020 ◽

Vol 92 (2) ◽

pp. 20601

Author(s):

Abdelaziz Labrag ◽

Mustapha Bghour ◽

Ahmed Abou El Hassan ◽

Habiba El Hamidi ◽

Ahmed Taoufik ◽

...

Keyword(s):

Magnetic Field ◽

Activation Energy ◽

Phase Diagram ◽

High Temperature ◽

Apparent Activation Energy ◽

High Temperature Superconductor ◽

Flux Flow ◽

Resistivity Measurements ◽

Vortex Phase ◽

The Magnetic Field

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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Contribution of superconducting grains and grain boundaries to the magnetoresistance of ceramic YBa2Cu3O7 − δ high-temperature superconductors in weak magnetic fields

Physics of the Solid State ◽

10.1134/s1063783410080044 ◽

2010 ◽

Vol 52 (8) ◽

pp. 1585-1592 ◽

Cited By ~ 7

Author(s):

T. V. Sukhareva ◽

V. A. Finkel’

Keyword(s):

High Temperature ◽

Magnetic Fields ◽

Grain Boundaries ◽

High Temperature Superconductors ◽

Weak Magnetic Fields

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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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Magnetized Black Holes: Ionized Keplerian Disks and Acceleration of Ultra-High Energy Particles

Proceedings ◽

10.3390/proceedings2019017013 ◽

2019 ◽

Vol 17 (1) ◽

pp. 13 ◽

Cited By ~ 3

Author(s):

Zdeněk Stuchlík ◽

Martin Kološ ◽

Arman Tursunov

Keyword(s):

Magnetic Field ◽

Black Holes ◽

Magnetic Fields ◽

High Energy ◽

Weak Magnetic Fields ◽

Motion Transformation ◽

Penrose Process ◽

Field Lines ◽

High Energy Particles ◽

Quasiperiodic Oscillations

Properties of charged particle motion in the field of magnetized black holes (BHs) imply four possible regimes of behavior of ionized Keplerian disks: survival in regular epicyclic motion, transformation into chaotic toroidal state, destruction due to fall into the BHs, destruction due to escape along magnetic field lines (escape to infinity for disks orbiting Kerr BHs). The regime of the epicyclic motion influenced by very weak magnetic fields can be related to the observed high-frequency quasiperiodic oscillations. In the case of very strong magnetic fields particles escaping to infinity could form UHECR due to extremely efficient magnetic Penrose process – protons with energy E > 10 21 eV can be accelerated by supermassive black holes with M ∼ 10 10 M ⊙ immersed in magnetic field with B ∼ 10 4 Gs.

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Small, modular and economically attractive fusion enabled by high temperature superconductors

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2018.0354 ◽

2019 ◽

Vol 377 (2141) ◽

pp. 20180354 ◽

Cited By ~ 4

Author(s):

Dennis Whyte

Keyword(s):

Magnetic Field ◽

High Temperature ◽

Magnetic Fields ◽

Current Density ◽

High Temperature Superconductors ◽

Fusion Energy ◽

High Magnetic Fields ◽

Operating Temperatures ◽

The Magnetic Field ◽

Game Changer

The advantages of high magnetic fields in tokamaks are reviewed, and why they are important in leading to more compact tokamaks. A brief explanation is given of what limits the magnetic field in a tokamak, and why high temperature superconductors (HTSs) are a game changer, not just because of their higher magnetic fields but also for reasons of higher current density and higher operating temperatures. An accelerated pathway to fusion energy is described, defined by the SPARC and ARC tokamak designs. This article is part of a discussion meeting issue ‘Fusion energy using tokamaks: can development be accelerated?’.

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