scholarly journals Tunnel Magnetoresistance of Fe3O4/MgO/Fe Nanostructures

2011 ◽  
Vol 2011 ◽  
pp. 1-3
Author(s):  
S. G. Chigarev ◽  
E. M. Epshtein ◽  
I. V. Malikov ◽  
G. M. Mikhailov ◽  
P. E. Zilberman
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Fields ◽  
Tunnel Junction ◽  
Magnetic Energy ◽  
Magnetic Tunnel Junction ◽  
Tunnel Magnetoresistance ◽  
Unidirectional Anisotropy ◽  
Layer Orientation ◽  
Layer Magnetization

A magnetic tunnel junction Fe3O4/MgO/Fe with (001) layer orientation is considered. The junction magnetic energy is analyzed as a function of the angle between the layer magnetization vectors under various magnetic fields. The tunnel magnetoresistance is calculated as a function of the external magnetic field. In contrast with junctions with unidirectional anisotropy, a substantially lower magnetic field is required for the junction switching.

scholarly journals The influence of an external magnetic field on the dynamics of magnetite reduction with hydrogen

RSC Advances ◽  
2021 ◽  
Vol 11 (25) ◽  
pp. 15422-15427
Author(s):  
Petr A. Chernavsky ◽  
Nellie V. Kim ◽  
Victor A. Andrianov ◽  
Yurii D. Perfiliev ◽  
Alla A. Novakova ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Fields ◽  
Hydrogen Reduction ◽  
Kinetics Of

The kinetics of hydrogen reduction of magnetite was investigated in different magnetic fields.

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

RSC Advances ◽  
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.

Flow Visualization by Means of Contactless Inductive Flow Tomography in the Presence of a Magnetic Brake

2015 ◽  
Vol 15 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Matthias Ratajczak ◽  
Thomas Wondrak ◽  
Klaus Timmel ◽  
Frank Stefani ◽  
Sven Eckert
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Fields ◽  
Flow Field ◽  
Continuous Casting ◽  
Flow Structure ◽  
Cross Section ◽  
Two Dimensional ◽  
Slab Casting ◽  
Two Dimensional Flow

AbstractIn continuous casting DC magnetic fields perpendicular to the wide faces of the mold are used to control the flow in the mold. Especially in this case, even a rough knowledge of the flow structure in the mold would be highly desirable. The contactless inductive flow tomography (CIFT) allows to reconstruct the dominating two-dimensional flow structure in a slab casting mold by applying one external magnetic field and by measuring the flow-induced magnetic fields outside the mold. For a physical model of a mold with a cross section of 140 mm×35 mm we present preliminary measurements of the flow field in the mold in the presence of a magnetic brake. In addition, we show first reconstructions of the flow field in a mold with the cross section of 400 mm×100 mm demonstrating the upward scalability of CIFT.

scholarly journals Room temperature giant magnetostriction in single-crystal nickel nanowires

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Anastasios Pateras ◽  
Ross Harder ◽  
Sohini Manna ◽  
Boris Kiefer ◽  
Richard L. Sandberg ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Single Crystal ◽  
Room Temperature ◽  
Magnetic Energy ◽  
Mechanical Energy ◽  
Three Dimensional ◽  
Local Strain ◽  
Nickel Nanowires ◽  
Giant Magnetostriction

Abstract Magnetostriction is the emergence of a mechanical deformation induced by an external magnetic field. The conversion of magnetic energy into mechanical energy via magnetostriction at the nanoscale is the basis of many electromechanical systems such as sensors, transducers, actuators, and energy harvesters. However, cryogenic temperatures and large magnetic fields are often required to drive the magnetostriction in such systems, rendering this approach energetically inefficient and impractical for room-temperature device applications. Here, we report the experimental observation of giant magnetostriction in single-crystal nickel nanowires at room temperature. We determined the average values of the magnetostrictive constants of a Ni nanowire from the shifts of the measured diffraction patterns using the 002 and 111 Bragg reflections. At an applied magnetic field of 600 Oe, the magnetostrictive constants have values of λ100 = −0.161% and λ111 = −0.067%, two orders of magnitude larger than those in bulk nickel. Using Bragg coherent diffraction imaging (BCDI), we obtained the three-dimensional strain distribution inside the Ni nanowire, revealing nucleation of local strain fields at two different values of the external magnetic field. Our analysis indicates that the enhancement of the magnetostriction coefficients is mainly due to the increases in the shape, surface-induced, and stress-induced anisotropies, which facilitate magnetization along the nanowire axis and increase the total magnetoelastic energy of the system.

scholarly journals 50. Magneto-hydrostatic equilibrium in an external magnetic field

1958 ◽  
Vol 6 ◽  
pp. 499-503 ◽  
Author(s):  
P. A. Sweet
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Electric Current ◽  
Virial Theorem ◽  
Magnetic Energy ◽  
Hydrostatic Equilibrium

The expression ∫∫∫all space ΔH2dv for a change in magnetic energy is shown to be incorrect when applied to a body carrying an electric current and situated in an external magnetic field. A modified expression is derived.Chandrasekhar's form of the virial theorem in a magnetic field is extended to the case where an external magnetic field is present.

Magnetic Field Dependence of Molecular Quantum Beat: Biacetyl

1980 ◽  
Vol 35 (11) ◽  
pp. 1271-1272 ◽  
Author(s):  
W. Henke ◽  
H. L. Selzle ◽  
T. R. Hays ◽  
E. W. Schlag
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Fields ◽  
Electronic State ◽  
Field Dependence ◽  
Magnetic Field Dependence ◽  
Laser Excitation ◽  
Quantum Beat ◽  
Narrow Bandwidth ◽  
Hypersonic Jet

Abstract The effect of an external magnetic field on the decay of an excited single rotational state of the 1Au electronic state of biacetyl is observed in a hypersonic jet experiment after narrow bandwidth laser excitation. The lifetime of the ex-cited state decreases already at low magnetic fields and the molecular quantum beat vanishes.

scholarly journals Are the photospheric sunspots magnetically force-free in nature?

2010 ◽  
Vol 6 (S273) ◽  
pp. 333-337 ◽  
Author(s):  
Sanjiv Kumar Tiwari
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Magnetic Fields ◽  
Magnetic Energy ◽  
Sufficient Conditions ◽  
Field Measurements ◽  
Magnetic Behaviour ◽  
Optical Telescope ◽  
Energy Gradient ◽  
Necessary And Sufficient

AbstractIn a force-free magnetic field, there is no interaction of field and the plasma in the surrounding atmosphere i.e., electric currents are aligned with the magnetic field, giving rise to zero Lorentz force. The computation of many magnetic parameters like magnetic energy, gradient of twist of sunspot magnetic fields (computed from the force-free parameter α), including any kind of extrapolations heavily hinge on the force-free approximation of the photospheric magnetic fields. The force-free magnetic behaviour of the photospheric sunspot fields has been examined by Metcalf et al. (1995) and Moon et al. (2002) ending with inconsistent results. Metcalf et al. (1995) concluded that the photospheric magnetic fields are far from the force-free nature whereas Moon et al. (2002) found the that the photospheric magnetic fields are not so far from the force-free nature as conventionally regarded. The accurate photospheric vector field measurements with high resolution are needed to examine the force-free nature of sunspots. We use high resolution vector magnetograms obtained from the Solar Optical Telescope/Spectro-Polarimeter (SOT/SP) aboard Hinode to inspect the force-free behaviour of the photospheric sunspot magnetic fields. Both the necessary and sufficient conditions for force-freeness are examined by checking global as well as as local nature of sunspot magnetic fields. We find that the sunspot magnetic fields are very close to the force-free approximation, although they are not completely force-free on the photosphere.

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