THRESHOLD VALUE FOR A SYMMETRY BREAKING EXTERNAL FIELD

1994 ◽  
Vol 08 (14n15) ◽  
pp. 929-935
Author(s):  
S. MALINOWSKI
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
External Field ◽  
Symmetry Breaking ◽  
Ground State ◽  
Threshold Value ◽  
Seebeck Coefficients

We discuss the problem of determination of the threshold value of external magnetic field breaking the ground state symmetry of a magnetic crystal. It is shown that for some magnetic crystals the threshold value of the field can be determined through relations between Peltier and Seebeck coefficients. An experiment to measure the threshold value of the field is proposed.

Theory of ground-state switching in an array of magnetic nanodots by application of a short external magnetic field pulse

2013 ◽  
Vol 87 (13) ◽  
Author(s):  
Roman Verba ◽  
Vasil Tiberkevich ◽  
Konstantin Guslienko ◽  
Gennadiy Melkov ◽  
Andrei Slavin
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Ground State ◽  
Magnetic Field Pulse ◽  
Field Pulse ◽  
Magnetic Nanodots ◽  
State Switching

SPIN-SPLITTING OF THE BOUND POLARON'S GROUND STATE BINDING ENERGY INDUCED BY THE RASHBA SPIN–ORBIT INTERACTION UNDER THE PERPENDICULAR MAGNETIC FIELD

2008 ◽  
Vol 22 (12) ◽  
pp. 1923-1932
Author(s):  
JIA LIU ◽  
ZI-YU CHEN
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Binding Energy ◽  
Ground State ◽  
Spin Splitting ◽  
Perpendicular Magnetic Field ◽  
Spin Orbit ◽  
Ground State Binding Energy ◽  
Bound Polaron ◽  
Rashba Spin

The influence of a perpendicular magnetic field on a bound polaron near the interface of a polar–polar semiconductor with Rashba effect has been investigated. The material is based on a GaAs / Al x Ga 1-x As heterojunction and the Al concentration varying from 0.2 ≤ x ≤ 0.4 is the critical value below which the Al x Ga 1-x As is a direct band gap semiconductor.The external magnetic field strongly altered the ground state binding energy of the polaron and the Rashba spin–orbit (SO) interaction originating from the inversion asymmetry in the heterostructure splitting of the ground state binding energy of the bound polaron. How the ground state binding energy will be with the change of the external magnetic field, the location of a single impurity and the electron area density have been shown in this paper, taking into account the SO coupling. The contribution of the phonons are also considered. It is found that the spin-splitting states of the bound polaron are more stable, and, in the condition of weak magnetic field, the Zeeman effect can be neglected.

THE GROUND-STATE PHASE DIAGRAMS OF THE SPIN-2 ISING MODEL

2007 ◽  
Vol 21 (31) ◽  
pp. 5265-5274 ◽  
Author(s):  
AHMET ERDİNÇ
Keyword(s):  
Magnetic Field ◽  
Ising Model ◽  
External Magnetic Field ◽  
Phase Diagrams ◽  
Crystal Field ◽  
Ground State ◽  
Exchange Interactions ◽  
Nearest Neighbors ◽  
Biquadratic Exchange ◽  
Model Hamiltonian

The ground-state phase diagrams are obtained for the spin-2 Ising model Hamiltonian with bilinear and biquadratic exchange interactions and a single-ion crystal field. The interactions are assumed to be only between nearest-neighbors. Obtained phase diagrams are presented in the (Δ,J), (K,J), (Δ/J,K/J), (Δ/|J|,K/|J|), (Δ/|K|,J/|K|), (H/J,Δ/J), (H/|J|,Δ/|J|), (H/J,K/J), and (H/|J|,K/|J|) planes where J, K, Δ, and H are the bilinear, biquadratic exchange interactions, the single-ion crystal field, and the external magnetic field, respectively. The influence of the external magnetic field on the spin configurations is investigated.

LANDAU LEVELS AND VERTEX OPERATIONS FOR ANYONS

1991 ◽  
Vol 06 (30) ◽  
pp. 2819-2826 ◽  
Author(s):  
GERALD V. DUNNE ◽  
ALBERTO LERDA ◽  
CARLO A. TRUGENBERGER
Keyword(s):  
Magnetic Field ◽  
Angular Momentum ◽  
External Magnetic Field ◽  
String Theory ◽  
Ground State ◽  
Correlation Functions ◽  
Landau Levels ◽  
Vertex Operators ◽  
Many Body

We construct exact many-body eigenstates of both energy and angular momentum for the N-anyon problem in an external magnetic field. We show that such states span the full ground state eigenspace and arise as correlation functions of Fubini-Veneziano vertex operators of string theory.

Infinite solitons in ferromagnetic materials with an internal magnetic field

2021 ◽  
pp. 2150413
Author(s):  
Hamdy I. Abdel-Gawad
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
External Field ◽  
Model Equation ◽  
Graphical Representation ◽  
Magnetic Moments ◽  
Soliton Solutions ◽  
Internal Magnetic Field ◽  
Multiple Soliton Solutions ◽  
The Magnetic Field

The ferromagnetism induced by an external magnetic field (EMF), in (3+1) dimensions, is governed by Kraenkel–Manna–Merle system (KMMS). A (1+1) dimension model equation was derived in the literature. The magnetic moments are parallel to the magnetic field in ferromagnetism as they are aligning in the same direction of the external field. Here, it is shown that the KMMS supports the presence of internal magnetic field. This may be argued to medium characteristics. The objective of this work is to mind multiple soliton solutions, which are obtained via the generalized together with extended unified methods. Graphical representation of the results are carried. They describe infinite soliton shapes, which arise from the multiple variation of the arbitrary functions in the solutions. It is, also, shown that internal magnetic field decays, asymptotically, to zero with time.

scholarly journals Simultaneous polydirectional transport of colloidal bipeds

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Mahla Mirzaee-Kakhki ◽  
Adrian Ernst ◽  
Daniel de las Heras ◽  
Maciej Urbaniak ◽  
Feliks Stobiecki ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
External Field ◽  
Colloidal Particles ◽  
Addition Reaction ◽  
Lab On A Chip ◽  
Magnetic Pattern ◽  
Colloidal Spheres ◽  
Colloidal Science ◽  
Colloidal Rods

Abstract Detailed control over the motion of colloidal particles is relevant in many applications in colloidal science such as lab-on-a-chip devices. Here, we use an external magnetic field to assemble paramagnetic colloidal spheres into colloidal rods of several lengths. The rods reside above a square magnetic pattern and are transported via modulation of the direction of the external magnetic field. The rods behave like bipeds walking above the pattern. Depending on their length, the bipeds perform topologically distinct classes of protected walks. We design parallel polydirectional modulation loops of the external field that command up to six classes of bipeds to walk on distinct predesigned paths. Using such loops, we induce the collision of reactant bipeds, their polymerization addition reaction to larger bipeds, the separation of product bipeds from the educts, the sorting of different product bipeds, and also the parallel writing of a word consisting of several letters. Our ideas and methodology might be transferred to other systems for which topological protection is at work.

scholarly journals A model of the response of GMR of metallic multilayers to external magnetic field

2015 ◽  
Vol 33 (4) ◽  
pp. 835-840
Author(s):  
J.I. Uba ◽  
A.J. Ekpunobi ◽  
P.I. Ekwo
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Giant Magnetoresistance ◽  
Ion Beam ◽  
Interface Roughness ◽  
Total Density ◽  
Metallic Multilayers ◽  
Interface Quality ◽  
Qualitative Measure

AbstractIt has not been possible to transform resistivity models in terms of magnetic field in order to account for variation of giant magnetoresistance (GMR) with external magnetic field, which would have led to determination of material properties. This problem is approached mathematically via variation calculus to arrive at an exponential function that fits observed GMR values. Using this model in free electron approximation, the mean Fermi vector, susceptibility and total density of states of a number of metallic multilayers are determined from their reported GMR values. Susceptibility is found to depend on interface roughness and antiferromagnetic (AF) coupling; thus, it gives qualitative measure of interface quality and AF coupling. Comparison of susceptibilities and GMRs of electrodeposited and ion beam sputtered Co/Cu structures shows that a rough interface suppresses GMR in the former but enhances it in the latter.

Whistler emission through transition radiation by a modulated electron beam spiralling in a magnetoplasma

2000 ◽  
Vol 63 (3) ◽  
pp. 285-295 ◽  
Author(s):  
M. STARODUBTSEV ◽  
C. KRAFFT
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
External Magnetic Field ◽  
Transition Radiation ◽  
Physical Processes ◽  
Phase Velocities ◽  
Electric Dipoles ◽  
Wave Emission ◽  
Loop Antennas

Transition radiation from the zone of injection of a modulated electron beam spiralling into a magnetoplasma has been identified as whistler waves propagating quasiparallel to the external magnetic field. The characteristics of the radiation are similar to the emission by localized sources, such as loop antennas and electric dipoles: resonance-cone structures at low plasma densities and energy flow along the external magnetic field at higher densities, with a diverging radiation pattern and with whistler phase velocities inversely proportional to the plasma frequency. These studies should contribute to a wider understanding of the physical processes connected with the injection of charges in a magnetoplasma – either from a gun on board a spacecraft or in a plasma chamber – and thus allow the determination of appropriate radiator characteristics in order to control, to some extent, plasma perturbations and wave emission in the region of the injector.

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