scholarly journals Stochastic dynamics of planar magnetic moments in a three-dimensional environment

2018 ◽  
Vol 510 ◽  
pp. 98-109 ◽  
Author(s):  
Zochil González Arenas ◽  
Daniel G. Barci ◽  
Miguel Vera Moreno
Keyword(s):  
Stochastic Dynamics ◽  
Magnetic Moments ◽  
Three Dimensional

Ternary Indides REMgIn (RE = Y, La–Nd, Sm, Gd–Tm, Lu). Synthesis, Structure and Magnetic Properties

2004 ◽  
Vol 59 (5) ◽  
pp. 513-518 ◽  
Author(s):  
Rainer Kraft ◽  
Martin Valldor ◽  
Daniel Kurowski ◽  
Rolf-Dieter Hoffmann ◽  
Rainer Pöttgen
Keyword(s):  
Magnetic Moments ◽  
Three Dimensional ◽  
Temperature Dependent ◽  
Variable Parameters ◽  
Magnetic Susceptibility Data ◽  
X Ray ◽  
Susceptibility Data ◽  
Sample Chamber ◽  
Trigonal Prismatic Coordination ◽  
Trigonal Prismatic

Abstract The equiatomic rare earth-magnesium-indium compounds REMgIn (RE = Y, La-Nd, Sm, Gd- Tm, Lu) were prepared from the elements in sealed tantalum tubes inside a water-cooled sample chamber of an induction furnace. All compounds were characterized through their X-ray powder patterns. They crystallize with the hexagonal ZrNiAl type structure, space group P6̄̄2m, with three formula units per cell. The structure of SmMgIn was refined from X-ray single crystal diffractometer data: a = 761.3(2), c = 470.3(1) pm, wR2 = 0.0429, 380 F2 values and 14 variable parameters. The DyMgIn, HoMgIn, and TmMgIn structures have been analyzed using the Rietveld technique. The REMgIn structures contain two cystallographically independent indium sites, both with tri-capped trigonal prismatic coordination: In1Sm6Mg3 and In2Mg6Sm3. Together the magnesium and indium atoms form a three-dimensional [MgIn] network with Mg-Mg distances of 320 and Mg-In distances in the range 294 - 299 pm. Temperature dependent magnetic susceptibility data show Curie-Weiss behavior for DyMgIn, HoMgIn, and TmMgIn with experimental magnetic moments of 11.0(1) μB/Dy atom, 10.9(1) μB/Ho atom, and 7.5(1) μB/Tm atom. The three compounds order antiferromagnetically at TN = 22(2) K (DyMgIn), 12(1) K (HoMgIn), and 3(1) K (TmMgIn).

scholarly journals Structural Evolution, Redox Mechanism, and Ionic Diffusion in Rhombohedral Na2FeFe(CN)6 for Sodium-Ion Batteries: First-Principles Calculations

2022 ◽  
Author(s):  
Ya-Ping Wang ◽  
B. P. Hou ◽  
Xin-Rui Cao ◽  
Shunqing Wu ◽  
Zi-Zhong Zhu
Keyword(s):  
First Principles ◽  
Rational Design ◽  
Low Cost ◽  
Magnetic Moments ◽  
Three Dimensional ◽  
Structural Evolution ◽  
Sodium Ion ◽  
High Rate ◽  
Sodium Ion Batteries ◽  
First Principles Calculations

Abstract Prussian blue analogs (Na2FeFe(CN)6) have been regarded as potential cathode materials for sodium-ion batteries (SIBs) due to their low-cost iron resources and open framework. Herein, the detailed first-principles calculations have been performed to investigate the electrochemical properties of NaxFeFe(CN)6 during Na ion extraction. The material undergoes a phase transition from a dense rhombohedral to open cubic structure upon half-desodiation, which is resulted from competition of the Na−N Coulomb attraction and d−π covalent bonding of Fe−N. The analyses on the density of states, magnetic moments and Bader charges of NaxFeFe(CN)6 reveal that there involve in the successive redox reactions of high-spin Fe2+/Fe3+ and low-spin Fe2+/Fe3+ couples during desodiation. Moreover, the facile three-dimensional diffusion channels for Na+ ions exhibit low diffusion barriers of 0.4 eV ~ 0.44 eV, which ensures a rapid Na+ transport in the NaxFeFe(CN)6 framework, contributing to high rate performance of the battery. This study gives a deeper understanding of the electrochemical mechanisms of NaxFeFe(CN)6 during Na+ extraction, which is beneficial for the rational design of superior PBA cathodes for SIBs.

Stochastic Bifurcations, Chaos and Phantom Attractors in the Langford System with Tori

2020 ◽  
Vol 30 (16) ◽  
pp. 2030051
Author(s):  
Irina Bashkirtseva ◽  
Lev Ryashko
Keyword(s):  
Dynamic Model ◽  
Gaussian Noise ◽  
Stochastic Dynamics ◽  
Three Dimensional ◽  
Stochastic Generation ◽  
Noise Amplification ◽  
Quasiperiodic Oscillations ◽  
Stochastic Bifurcations

The variability of stochastic dynamics for a three-dimensional dynamic model in a parametric zone with 2-tori is investigated. It is shown how weak Gaussian noise transforms deterministic quasiperiodic oscillations into noisy bursting. The phenomenon of stochastic generation of a phantom attractor and its shift with noise amplification is revealed. This phenomenon, accompanied by order-chaos transitions, is studied in terms of stochastic [Formula: see text]- and [Formula: see text]-bifurcations.

scholarly journals BARYONS AS SOLITONS IN THREE-DIMENSIONAL QUANTUM CHROMODYNAMICS

1992 ◽  
Vol 07 (32) ◽  
pp. 8001-8019 ◽  
Author(s):  
G. FERRETTI ◽  
S.G. RAJEEV ◽  
Z. YANG
Keyword(s):  
Quantum Chromodynamics ◽  
Quark Model ◽  
Magnetic Moments ◽  
Three Dimensional ◽  
Collective Variables ◽  
Soliton Model ◽  
Quantum Numbers ◽  
Effective Lagrangian ◽  
Quantum Antiferromagnet

We show that baryons of three-dimensional quantum chromodynamics can be understood as solitons of its effective Lagrangian. In the parity-preserving phase we study, these baryons are fermions for odd Nc and bosons for even Nc, never anyons. We quantize the collective variables of the solitons and thereby calculate the flavor quantum numbers. magnetic moments and mass splittings of the baryon. The flavor quantum numbers are in agreement with naive quark model for the low-lying states. The magnetic moments and mass splittings are smaller in the soliton model by a factor of logFπ/Ncmπ. We also show that there is a dibaryon solution that is an analog of the deuteron. These solitons can describe defects in a quantum antiferromagnet.

scholarly journals Stochastic Dynamics of Lagrangian Pore‐Scale Velocities in Three‐Dimensional Porous Media

2019 ◽  
Vol 55 (2) ◽  
pp. 1196-1217 ◽  
Author(s):  
Alexandre Puyguiraud ◽  
Philippe Gouze ◽  
Marco Dentz
Keyword(s):  
Porous Media ◽  
Stochastic Dynamics ◽  
Three Dimensional ◽  
Pore Scale

scholarly journals Magnetic field amplification in electron phase-space holes and related effects

2012 ◽  
Vol 30 (4) ◽  
pp. 711-724 ◽  
Author(s):  
R. A. Treumann ◽  
W. Baumjohann
Keyword(s):  
Magnetic Field ◽  
Phase Space ◽  
Flux Tube ◽  
Magnetic Moments ◽  
Three Dimensional ◽  
Cosmic Ray ◽  
Magnetic Fabric ◽  
Magnetic Field Generation ◽  
Electron Holes ◽  
The Magnetic Field

Abstract. Three-dimensional electron phase-space holes are shown to have positive charges on the plasma background, which produce a radial electric field and force the trapped electron component into an azimuthal drift. In this way electron holes generate magnetic fields in the hole. We solve the cylindrical hole model exactly for the hole charge, electric potential and magnetic field. In electron holes, the magnetic field is amplified on the flux tube of the hole; equivalently, in ion holes the field would be decreased. The flux tube adjacent to the electron hole is magnetically depleted by the external hole dipole field. This causes magnetic filamentation. It is also shown that holes are massive objects, each carrying a finite magnetic moment. Binary magnetic dipole interaction of these moments will cause alignment of the holes into chains along the magnetic field or, in the three-dimensional case, produce a magnetic fabric in the volume of hole formation. Since holes, in addition to being carriers of charges and magnetic moments, also have finite masses, they behave like quasi-particles, performing E × B, magnetic field, and diamagnetic drifts. In an inhomogeneous magnetic field, their magnetic moments experience torque, which causes nutation of the hole around the direction of the magnetic field, presumably giving rise to low frequency magnetic modulations like pulsations. A gas of many such holes may allow for a kinetic description, in which holes undergo binary dipole interactions. This resembles the polymeric behaviour. Both magnetic field generation and magnetic structure formation are of interest in auroral, solar coronal and shock physics, in particular in the problem of magnetic field filamentation in relativistic foreshocks and cosmic ray acceleration.

MAGNETIC MOMENT OF 2-DIMENSIONAL AND 3-DIMENSIONAL MANY-ELECTRON SYSTEMS EXAMINED WITH DEPENDENCE ON A COMMON SIZE PARAMETER

2002 ◽  
Vol 16 (30) ◽  
pp. 1183-1191
Author(s):  
S. OLSZEWSKI
Keyword(s):  
Magnetic Moment ◽  
Magnetic Moments ◽  
Electron Gas ◽  
Three Dimensional ◽  
Electron Systems ◽  
Size Parameter ◽  
3 Dimensional ◽  
Cubic Lattice ◽  
Simple Cubic ◽  
The Moment

The orbital magnetic moments induced by a constant magnetic field in a two-dimensional (2D) and three-dimensional (3D) electron gas are calculated on the same footing independent of the conventional method based on statistical thermodynamics. The dependence of the moment on a common size parameter — defined as the cubic root of the volume occupied by one electron in a 3D gas — is found to be a similar monotonic function for both kinds of electron gas. This monotonic dependence is compared with the oscillating function of the size parameter obtained for the magnetic moment calculated in the case of a 2D slice of the tightly-bound s-electron states in a simple-cubic, or body-centred cubic, lattice.

LOCAL ORDER OF LIQUID AND UNDERCOOLED TRANSITION METAL BASED SYSTEMS: AB INITIO MOLECULAR DYNAMICS STUDY

2006 ◽  
Vol 20 (12) ◽  
pp. 655-674 ◽  
Author(s):  
NOEL JAKSE ◽  
ALAIN PASTUREL
Keyword(s):  
Molecular Dynamics ◽  
Transition Metals ◽  
Ab Initio ◽  
Liquid State ◽  
Magnetic Moments ◽  
Three Dimensional ◽  
Ab Initio Molecular Dynamics ◽  
Local Order ◽  
Pure Liquid ◽  
Common Neighbor

An overview of a recent series of ab initio molecular dynamics (MD) simulations for pure liquid transition metals as well as for transition metals (TM) based liquid alloys is presented. The aim is to investigate the local structure of these systems and their evolution upon undercooling, and our results are analyzed through a three-dimensional picture of the short-ranger order (SRO) by means of the common-neighbor analysis. Recent diffraction experiments indicate that the structure of both pure metals and alloys in undercooled states is dominated by an icosahedral SRO. We find that the five-fold symmetry is already present in the liquid state of all the studied systems. However our findings show that the five-fold symmetry in the liquid state as well as its evolution upon undercooling depends on the system under consideration. For Ni , Zr , and Ta , local configurations are more complex than that given by the simple icosahedron. For Al 80 Ni 20 and Al 80 Mn 20 alloys, local configurations are the result of a strong competition between chemical and topological effects; the key role played by the occurrence of localized magnetic moments of Mn atoms to interpret their short-range arrangements is emphasized, and the time evolution of the configurations is examined in terms of the mean square displacements.

Theoretical Study of Geometries, Stabilities, and Electronic Properties of Cationic (FeS)n+ (n = 1–5) Clusters

2016 ◽  
Vol 71 (1) ◽  
pp. 45-51 ◽  
Author(s):  
A. Li-Ta ◽  
Zhang Yu ◽  
Bai Jian-Ping ◽  
Zhang Shuai ◽  
Li Gen-Quan ◽  
...  
Keyword(s):  
Density Functional ◽  
Global Minimum ◽  
Magnetic Moments ◽  
Three Dimensional ◽  
Binding Energies ◽  
Functional Theory ◽  
Ground State Structures ◽  
Homo Lumo ◽  
Geometric Optimisation ◽  
Theoretical Results

AbstractWe have performed unbiased searches for the global minimum structures of (FeS)n+ (n=1–5) clusters using the CALYPSO method combined with density functional theory geometric optimisation. A large number of low-lying isomers are optimised at the B3PW91/6-311+G* theory level. Accurate ab initio calculations and harmonic vibrational analyses are undertaken to ensure that the optimised geometries are true minimum. They show that the most stable structures begin to exhibit three-dimensional (3D) configurations at n=3. The relative stabilities of (FeS)n+ clusters for the ground-state structures are analysed on the basis of binding energies and HOMO-LUMO gaps. The theoretical results indicate that the binding energies of (FeS)n+ tend to increase with cluster size. The maxima of HOMO-LUMO gaps (3.88 eV) for the most stable configurations appear at (FeS)+. Moreover, we have found that the (FeS)2+ cluster possesses the lowest local magnetic moments compared to the other species. The origin of this magnetic phenomenon is also analysed in detail.

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