Effects of Magnetic Anisotropy on Total Magnetic Field Anomalies

Theoretically, with the aid of a soliton model, the evolution of a new-phase nucleus near the first-order spin-reorientation phase transition in magnets has been investigated in an external magnetic field. The influence of an external field and one-dimensional defects of magnetic anisotropy on the dynamics of such nucleus has been demonstrated. The conditions for the localization of the new-phase nucleus in the region of the magnetic anisotropy defect and for its escape from the defect have been determined. The values of the critical fields which bring about the sample magnetization reversal have been identified and estimated.

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The Magnetic Anisotropy of Stretched Rubber as a Function of the Tension to Which It Is Subjected

Rubber Chemistry and Technology ◽

10.5254/1.3543206 ◽

1945 ◽

Vol 18 (1) ◽

pp. 8-9 ◽

Cited By ~ 1

Author(s):

Eugénie Cotton-Feytis

Keyword(s):

Magnetic Field ◽

Magnetic Anisotropy ◽

Uniaxial Crystal ◽

Horizontal Magnetic Field ◽

First Approximation ◽

The Difference ◽

The Times ◽

Angular Displacements ◽

The Magnetic Field ◽

Oscillation Method

Abstract From the standpoint of its magnetic anisotropy, stretched rubber is comparable in a first approximation to a uniaxial crystal, in which the direction of the axis is the same as the direction of elongation. It is possible to measure this anisotropy by means of the oscillation method used by Krishnan, Guha and Banerjee in studying crystals. The sample to be examined is suspended in a uniform horizontal magnetic field in such a manner that its axis is horizontal. It is then so arranged that the torsion of the suspension wire is zero when the rubber sample is in a position of equilibrium in the field. The times of oscillation T′ and T for very small angular displacements around this position, in the presence and then in the absence of the magnetic field, are then recorded. In this way the difference between the specific susceptibilities in the direction of the axis and in the horizontal direction perpendicular to the axis is calculated by application of the equation:

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High Frequency Magnetoimpedance of FeNi/Cu/FeNi Sensitive Elements with Different Geometries

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.152-153.373 ◽

2009 ◽

Vol 152-153 ◽

pp. 373-376 ◽

Cited By ~ 4

Author(s):

Stanislav O. Volchkov ◽

Andrey V. Svalov ◽

G.V. Kurlyandskaya

Keyword(s):

Magnetic Field ◽

Experimental Data ◽

External Magnetic Field ◽

Finite Elements ◽

Magnetic Anisotropy ◽

Constant Magnetic Field ◽

High Frequency ◽

Complex Impedance ◽

Rf Sputtering ◽

Frequency Range

In this work magnetoimpedance (MI) behaviour was studied experimentally for Fe19Ni81(175 nm)/Cu(350 nm)/Fe19Ni81(175 nm) sensitive elements deposited by rf-sputtering. A constant magnetic field was applied in plane of the sandwiches during deposition perpendicular to the Cu-lead in order to induce a magnetic anisotropy. Sandwiches with different width (w) of FeNi parts were obtained. The complex impedance was measured as a function of the external magnetic field for a frequency range of 1 MHz to 700 MHz for MI elements with different geometries. Some of MI experimental data are comparatively analysed with finite elements numerical calculations data. The obtained results can be useful for optimization of the design of miniaturized MI detectors.

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Preferred orientation of ferromagnetic phases in rock-forming minerals: insights from magnetic anisotropy of single crystals

Canadian Journal of Earth Sciences ◽

10.1139/cjes-2018-0172 ◽

2019 ◽

Vol 56 (9) ◽

pp. 994-1001 ◽

Cited By ~ 1

Author(s):

Ann M. Hirt ◽

Andrea R. Biedermann

Keyword(s):

Magnetic Field ◽

Magnetic Anisotropy ◽

Single Crystals ◽

Remanent Magnetization ◽

Igneous Rocks ◽

Flow Structures ◽

Silicate Minerals ◽

Fine Grained ◽

Crystallographic Axes ◽

Paleomagnetic Direction

In the early days of paleomagnetism, David Strangway was interested in understanding why igneous rocks are faithful recorders of the Earth’s magnetic field. He recognized that ferromagnetic (s.l.) grains that could be discerned by optical microscopy were too large to carry a stable remanent magnetization, and speculated whether fine-grained, ferromagnetic (s.l.) inclusions or exsolutions in silicate minerals are responsible. When these inclusions or exsolutions are randomly oriented, or the silicate hosts are randomly oriented in a rock, they can be a good recorder of the field. If these minerals, however, show an alignment within the silicate host, and the host is preferentially aligned due to flow structures or deformation, then the paleomagnetic direction and paleointensity could be biased. We examine the magnetic anisotropy arising from the ferromagnetic (s.l.) phases in silicate-host minerals. Single crystals of phyllosilicate, clinopyroxene, and calcite show most consistent ferrimagnetic fabric with relation to the minerals’ crystallographic axes, whereas olivine and feldspar display only a weak relationship. No discernable relationship is found between the ferrimagnetic anisotropy and crystallographic axes for amphibole minerals. Our results have implications when single crystals are being used for either studies of field direction or paleointensity or in cases where silicate minerals have a preferential orientation. Phyllosilicate minerals and pyroxene should be screened for significant magnetic anisotropy.

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