scholarly journals Mathematical modeling of the magnetic properties of spheroids of hard second kind superconductors in the Bean model

2019 ◽  
Vol 21 (3) ◽  
pp. 353-362 ◽  
Author(s):  
Nikolay D. Kuzmichev ◽  
Aleksey A. Shushpanov ◽  
Mihail A. Vasyutin
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Induction ◽  
Hysteresis Loops ◽  
Uniform Grid ◽  
Bean Model ◽  
The Poisson Equation ◽  
Equations Of Electrodynamics ◽  
Current Voltage ◽  
Sample Density ◽  
Current Sample

Authors have modelled magnetic field in hard II-type superconductor bodies with cylindric symmetry by means of Bean model. Using the equations of electrodynamics and the Poisson equation for the vector potential, the Fredholm equation of the first kind is derived for the screening supercurrent density. By introducing the explicit form of the current-voltage characteristic and the law of electromagnetic induction, the equation for the supercurrent density is reduced to an integral equation of the 2nd kind, which is solved numerically in matrix form on a non-uniform grid with compaction to the edges of the sample. Density distribution of the screened superconductive current, sample-self magnetic field and hysteresis loops of magnetization in the cases of cylinders and spheroids are obtained.

scholarly journals Heat Transfer Study of the Ferrofluid Flow in a Vertical Annular Cylindrical Duct under the Influence of a Transverse Magnetic Field

Fluids ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 120
Author(s):  
Panteleimon Bakalis ◽  
Polycarpos Papadopoulos ◽  
Panayiotis Vafeas
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Field Strength ◽  
Circular Cross Section ◽  
Transverse Magnetic ◽  
Uniform Grid ◽  
Volumetric Concentration ◽  
Flow And Heat Transfer ◽  
Axial Pressure Gradient ◽  
Transfer Study

We studied the laminar fully developed ferrofluid flow and heat transfer phenomena of an otherwise magnetic fluid into a vertical annular duct of circular cross-section and uniform temperatures on walls which were subjected to a transverse external magnetic field. A computational algorithm was used, which coupled the continuity, momentum, energy, magnetization and Maxwell’s equations, accompanied by the appropriate conditions, using the continuity–vorticity–pressure (C.V.P.) method and a non-uniform grid. The results were obtained for different values of field strength and particles’ volumetric concentration, wherein the effects of the magnetic field on the ferrofluid flow and the temperature are revealed. It is shown that the axial velocity distribution is highly affected by the field strength and the volumetric concentration, the axial pressure gradient depends almost linearly on the field strength, while the heat transfer significantly increases due to the generated secondary flow.

Preparation and Electrical Characteristics of (100), (111), and Randomly Oriented PZT Thin Films

1994 ◽  
Vol 361 ◽  
Author(s):  
Chang Jung Kim ◽  
Dae Sung Yoon ◽  
Joon Sung Lee ◽  
Chaun Gi Choi ◽  
Won Jong Lee ◽  
...  
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Hysteresis Loops ◽  
Test System ◽  
Electrical Characteristics ◽  
Pzt Thin Films ◽  
Pole Figures ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Drying Conditions

ABSTRACTThe (100), (111) and randomly oriented PZT thin films were fabricated on Pt/Ti/Coming 7059 glass using sol-gel method. The thin films having different orientation were fabricated by different drying conditions for pyrolysis. The preferred orientations of the PZT thin films were observed using XRD, rocking curves, and pole figures. The microstructures were investigated using SEM. The hysteresis loops and capacitance-voltage characteristics of the films were investigated using a standardized ferroelectric test system. The dielectric constant and current-voltage characteristics of the films were investigated using an impedance analyzer and pA meter, respectively. The films oriented in a particular direction showed superior electrical characteristics to the randomly oriented films.

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

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.

Non-linear dynamics of the Villari effect in the presence of a non-homogeneous magnetic field

2018 ◽  
Vol 233 (4) ◽  
pp. 431-440
Author(s):  
Andrzej Rysak ◽  
Magdalena Gregorczyk
Keyword(s):  
Magnetic Field ◽  
Time Series ◽  
Hysteresis Loops ◽  
Bias Field ◽  
Homogeneous Magnetic Field ◽  
Operating Conditions ◽  
Bias Magnetic Field ◽  
Linear Dynamics ◽  
Non Linear ◽  
Magnetostrictive Devices

Investigations of systems with an active magnetostrictive element generally assume the presence of an external homogeneous bias magnetic field. This article, however, presents the results of a study investigating a bimorph magnetostrictive-aluminium beam vibrating in a non-homogeneous bias field. By comparing results obtained under different operating conditions of the system, the combined effect of the non-linear beam stress and the non-homogeneous external magnetic field on the dynamics of the Villari phenomenon is determined. The preliminary results prove that the application of non-linear magnetic fields to the magnetostrictive devices ensures the extension of energy harvesting bandwidth of these devices and can be used to improve their control possibilities. A study of time series and hysteresis loops provides more detailed information about the non-linear magnetization and dynamics of the system.

scholarly journals On the crustal bias of repeat stations in Romania

2013 ◽  
Vol 55 (6) ◽  
Author(s):  
Venera Dobrica ◽  
Crisan Demetrescu ◽  
Razvan Greculeasa ◽  
Anca Isac
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Curie Temperature ◽  
Magnetic Induction ◽  
Electromagnetic Induction ◽  
Reference Station ◽  
Lateral Variation ◽  
Field Campaigns ◽  
Induction Model ◽  
Geomagnetic Measurements

<p>A magnetic induction model has been applied to recordings obtained in 2010 during the field campaigns for geomagnetic measurements at the 26 repeat stations of the Romanian secular variation network. The model is based on the observation that a variable external magnetic field induces a response of the Earth's interior not only by electromagnetic induction, but also by magnetic induction in the magnetic rocks above the Curie temperature. The model computes coefficients of a linear relationship between recorded values of a certain geomagnetic element (X, Y, Z, or F) at the repeat station and recorded X, Y, Z values at a reference station (in this case, SUA observatory). Coefficients depend on magnetic permeabilities of rocks beneath the station and stand as a proxy for the anomaly bias characterizing the site. Maps of the lateral variation of this type of information were obtained and discussed.</p>

scholarly journals Numerical simulation of induction heating thick-walled tubes

2018 ◽  
Vol 168 ◽  
pp. 02004
Author(s):  
Richard Lenhard ◽  
Milan Malcho ◽  
Katarína Kaduchová
Keyword(s):  
Magnetic Field ◽  
Numerical Simulation ◽  
Field Distribution ◽  
Induction Heating ◽  
Electromagnetic Induction ◽  
Magnetic Field Distribution ◽  
The Magnetic Field ◽  
Heated Material ◽  
Ansys Workbench

In the paper is shown the connection of two toolboxes in an Ansys Workbench solution for induction heating. In Ansys Workbench, Maxwell electromagnetism programs and Fluent have been linked. In Maxwell, a simulation of electromagnetic induction was performed, where data on the magnetic field distribution in the heated material was obtained and then transformed into the Fluent program in which the induction heating simulation was performed.

Ferroelectric Property and Microstructures of La-Doped Bi4Ti3O12 Thin Films

2013 ◽  
Vol 537 ◽  
pp. 114-117
Author(s):  
X.A. Mei ◽  
Rui Fang Liu ◽  
C.Q. Huang ◽  
J. Liu
Keyword(s):  
Thin Films ◽  
Hysteresis Loops ◽  
Differential Resistance ◽  
Rf Magnetron Sputtering ◽  
Layered Perovskite ◽  
Random Orientation ◽  
Si Substrates ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
La Doped

La-doped bismuth titanate (Bi4-xLaxTi3O12: BLT) and pure Bi4Ti3O12 (BIT) thin films with random orientation were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique. These samples had polycrystalline Bi-layered perovskite structure without preferred orientation, and consisted of well developed rod-like grains with random orientation. For the samples with x=0.25 and 1.0 the current-voltage characteristics exhibited negative differential resistance behaviors and their P-V hysteresis loops were characterized by large leakage current, whereas for the samples with x=0.5 and 0.75 the current-voltage characteristics showed simple ohmic behaviors and their P-V hysteresis loops were the saturated and undistorted hysteresis loops. The remanent polarization ( Pr ) and coercive field (Ec) of the BLT ceramic with x=0.75 were above 20μC/cm2 and 85KV/cm , respectively.

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