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Magnetization Curve (magnetization + curve)

Distribution by Scientific Domains

Physics and Astronomy	66%

Selected Abstracts

Highly crystalline cobalt nanowires with high coercivity prepared by soft chemistry

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 4 2009
G. Viau
Abstract Cobalt nanorods and wires were prepared by reduction of a cobalt salt in a liquid polyol. These particles crystallize with the hcp structure and the growth axis is parallel to the crystallographic c -axis. The kinetic control of the growth allows to vary the mean diameter of the rods and their aspect ratio. Dumbbell like shape particles consisting of a central rod with two conical tips were also obtained. Magnetization curves of oriented wires present very high coercivity (up to 9 kOe) resulting from both a high shape anisotropy and the high magnetocrystalline anisotropy of the hcp cobalt. Micromagnetic simulations showed that the magnetization reversal is shape dependent. The conical tips of the dumbbell particles strongly contribute to the coercivity decrease and must be precluded for permanent magnet applications. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Magnetization and FMR studies of [Fe/Cr]n structures with ultrathin iron layers

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2006
A. B. Drovosekov
Abstract Magnetic multilayer structures [Fe(tFe)/Cr(tCr)]n with ultrathin (tFe < 5 Å) iron layers prepared by a molecular beam epitaxy were studied using SQUID-magnetometry and ferromagnetic resonance technique. For the samples with tFe , 3 Å, the obtained magnetization curves and resonance spectra are typical for regular magnetic superlattices. On the contrary, the samples with tFe , 3 Å demonstrate superparamagnetic-like behavior. These samples show a strong temperature dependence of their static and resonance magnetic properties. To explain the obtained results, we propose a theoretical model considering a cluster structure of thin iron layers. Magnetization curves and resonance spectra are calculated using an effective field approximation taking into account an interlayer interaction and cluster size distribution. The calculated dependencies show a qualitative agreement with the experimental data. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

A systematic method for the development of a three-phase transformer non-linear model

INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 8 2010
Andreas D. Theocharis
Abstract In this work, a novel three-phase transformer non-linear model is developed. The proposed model takes into account the magnetic core topology and the windings connections. The non-linear characteristic curve of the core material is introduced by its magnetization curve or by its hysteresis loop using the mathematical hysteresis model proposed by Tellinen or the macroscopic hysteresis model proposed by Jiles,Atherton. The eddy currents effects are included through non-linear resistors using Bertotti's work. The proposed model presents several advantages. An incremental linear circuit, having the same topology with the magnetic circuit of the core, is used in order to directly write the differential equations of the magnetic part of the transformer. The matrix Ld that describes the coupling between the windings of the transformer is systematically derived. The electrical equations of the transformer can be easily written for any possible connection of the primary and secondary windings using the unconnected windings equations and transformation matrices. The proposed methods for the calculation of the coupling between the windings, the representation of the eddy currents and the inclusion of the core material characteristic curve can be used to develop a transformer model appropriate for the EMTP/ATP-type programs. Copyright © 2009 John Wiley & Sons, Ltd. [source]

A Simple Sol,Gel Synthesis of Superconducting MgB2 Nanowires,

ADVANCED MATERIALS, Issue 14 2006
M. Nath
Superconducting MgB2 nanowires have been synthesized in a very high yield by a simple soft-chemical approach combining sol-gel chemistry and pyrolysis techniques (see main image in the figure; scale bar: 10,,m). The long thin nanowires show a superconducting transition temperature, Tc, of ca.,39,K, as shown in the magnetization curve in the inset of the figure. [source]

Approximation of magnetic behavior of complex nanomagnetic materials, using the "P " curves for structural characterization of magnetic suspensions

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2008
N. C. Popa
Abstract The "P " curves for the structural characterization of magnetic nanoparticles suspensions (complex fluids, complex powders, complex composite materials, or living biological materials having magnetic properties) are the graphical representation of the first derivative (relative to the magnetic field strength H) of the magnetization curve relative to its saturation magnetization. In the case of the above materials, the magnetic properties are conferred to various carrier liquids by artificially integrating in their structure ferromagnetic particles of different sizes. The magnetic properties are usually shown by the hysteresis curve. The structure can be seen by (electronic) micrography. The P curves offer another possibility to determine the structure of the magnetic component of a complex fluid by numerical analysis of the magnetization curve experimentally obtained. Starting from these P curves, the paper presents the possibility to approximate the magnetic behavior of these complex nanomagnetic materials. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]