The Role of Next-Nearest Neighbors in The Neel Model of Surface Anisotropy for BCC Crystals

1991 ◽  
Vol 231 ◽  
Author(s):  
Robert L. White ◽  
Bruce M. Clemens
Keyword(s):  
Experimental Data ◽  
Thin Films ◽  
Nearest Neighbor ◽  
Nearest Neighbors ◽  
Surface Anisotropy ◽  
Neighbor Interaction ◽  
Dominant Source ◽  
Cast Doubt

AbstractWe have extended the Neél model of surface anisotropy in b.c.c. crystals to include next nearest neighbor interaction. Fitting the experimental data for Fe (001) and (110) surfaces leads to some pradoxes which cast doubt on the Neél surface anisotropy as the dominant source of surface anisotropy in thin films.

scholarly journals ON SPATIAL CONSENSUS FORMATION: IS THE SZNAJD MODEL DIFFERENT FROM A VOTER MODEL?

2003 ◽  
Vol 14 (10) ◽  
pp. 1331-1354 ◽  
Author(s):  
LAXMIDHAR BEHERA ◽  
FRANK SCHWEITZER
Keyword(s):  
Computer Simulations ◽  
Nearest Neighbor ◽  
Temporal Evolution ◽  
Relaxation Times ◽  
Nearest Neighbors ◽  
Voter Model ◽  
Consensus Formation ◽  
Spatio Temporal ◽  
Update Rules

In this paper, we investigate the so-called "Sznajd Model" (SM) in one dimension, which is a simple cellular automata approach to consensus formation among two opposite opinions (described by spin up or down). To elucidate the SM dynamics, we first provide results of computer simulations for the spatio-temporal evolution of the opinion distribution L(t), the evolution of magnetization m(t), the distribution of decision times P(τ) and relaxation times P(μ). In the main part of the paper, it is shown that the SM can be completely reformulated in terms of a linear voter model (VM), where the transition rates towards a given opinion are directly proportional to frequency of the respective opinion of the second-nearest neighbors (no matter what the nearest neighbors are). So, the SM dynamics can be reduced to one rule, "Just follow your second-nearest neighbor". The equivalence is demonstrated by extensive computer simulations that show the same behavior between SM and VM in terms of L(t), m(t), P(τ), P(μ), and the final attractor statistics. The reformulation of the SM in terms of a VM involves a new parameter σ, to bias between anti- and ferromagnetic decisions in the case of frustration. We show that σ plays a crucial role in explaining the phase transition observed in SM. We further explore the role of synchronous versus asynchronous update rules on the intermediate dynamics and the final attractors. As compared to the original SM, we find three additional attractors, two of them related to an asymmetric coexistence between the opposite opinions.

PHASE TRANSITIONS OF THE MIXED-SPIN ISING MODEL ON A DECORATED LATTICE WITH THE NEAREST-NEIGHBOR INTERACTION BETWEEN DECORATING SPINS

2009 ◽  
Vol 23 (24) ◽  
pp. 4963-4976 ◽  
Author(s):  
A. BENYOUSSEF ◽  
A. EL KENZ ◽  
M. EL YADARI ◽  
M. LOULIDI
Keyword(s):  
Phase Transitions ◽  
Ising Model ◽  
Phase Diagrams ◽  
Nearest Neighbor ◽  
Mean Field ◽  
Nearest Neighbors ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Neighbor Interaction ◽  
Mixed Spin

A mean-field approximation is developed for a decorated ferrimagnetic Ising model, in which the two magnetic atoms A and B have spins σ=1/2 and S=1, respectively. In this system, the exchange interaction between nearest-neighbors of atom B is taken into account. Some interesting phenomena, such as the appearance of three types of phase diagrams and the existence of one and two compensation points are found. Phase diagrams and temperature dependence of the magnetizations of the system are investigated in detail.

scholarly journals Antiferromagnetic and Ferromagnetic Spintronics: Transport in the Two-dimensional Ferromagnet and the Role of In-chain and Inter-chain Interactions

2021 ◽  
Author(s):  
L. S. Lima
Keyword(s):  
Nearest Neighbor ◽  
Nearest Neighbors ◽  
Two Dimensional ◽  
Spin Correlations ◽  
Ferromagnetic Domain ◽  
Frustrated Spin ◽  
Ferromagnetic Domain Wall ◽  
Chain Interaction ◽  
The Continuum

Abstract Spin-transport and current-induced torques in ferromagnet heterostruc-tures given by a ferromagnetic domain wall are investigated. Furthermore , the continuum spin conductivity is studied in a frustrated spin system given by the two-dimensional Heisenberg model with ferromagnetic in-chain interaction J 1 < 0 between nearest neighbors and antiferromagnetic next-nearest-neighbor in-chain interaction J 2 > 0 with aim to investigate the effect of the phase diagram of the critical ion single anisotropy D c as a function of J 2 on conductivity. We consider the model with the moderate strength of the frustrating parameter such that in-chain spin-spin correlations that are predominantly ferromagnetic. In addition, we consider two inter-chain couplings J ⊥,y and J ⊥,z , corresponding to the two axes perpendicular to chain where ferromagnetic as well as antiferromagnetic interactions are taken into account.

Nucleation and Growth of Diamond Thin Films: The Role of Temperature and Pressure

2010 ◽  
Vol 1278 ◽  
Author(s):  
J. Morales ◽  
R. Bernal ◽  
C. Cruz-Vazquez ◽  
E.G. Salcido-Romero ◽  
V.M. Castaño
Keyword(s):  
Experimental Data ◽  
Thin Films ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Nucleation And Growth ◽  
Liquid Injection ◽  
Crystal Diameter ◽  
Temperature And Pressure ◽  
Diamond Thin Films

AbstractDiamond thin films were deposited onto Si (100) substrates using liquid a solution of water and acetone, ethanol, methanol and commercial Tequila as precursors by the Pulsed Liquid Injection Chemical Vapor Deposition (PLICVD) technique. Temperature was varied from 550 °C to 850 °C. In this work we attempted to find a crystal diameter dependence on temperature and pressure from the experimental data. The goal in this work is to found a function that can be adjusted to the experimental data.

Computer simulation of phase transitions of the Heisenberg antiferromagnetic model

2019 ◽  
pp. 25-31
Author(s):  
M.K. Ramazanov ◽  
A.K. Murtazaev
Keyword(s):  
Computer Simulation ◽  
Phase Transitions ◽  
Nearest Neighbor ◽  
Three Dimensional ◽  
Exchange Interactions ◽  
Nearest Neighbors ◽  
Neighbor Interaction ◽  
A Value ◽  
The Monte Carlo Method ◽  
Antiferromagnetic Model

Based on the replica algorithm by the Monte Carlo method, a computer simulation of the three-dimensional antiferromagnetic Heisenberg model is performed, taking into account the interactions of the first and second nearest neighbors. The phase transitions of this model are studied. The investigations were carried out for the ratios of the exchange interactions of the first and second nearest neighbors $r = J_2 / J_1$ in the range $0.0 \leq r \leq 1.0$. The phase diagram of the critical temperature dependence on a value of the next-nearest neighbor interaction is plotted.

INSIGNIFICANT NEXT NEAREST NEIGHBOR EFFECT IN Ni(II)-[2×2] GRID

2006 ◽  
Vol 20 (16) ◽  
pp. 971-979 ◽  
Author(s):  
ALI BAYRI
Keyword(s):  
Experimental Data ◽  
Energy Spectrum ◽  
Heisenberg Model ◽  
Nearest Neighbor ◽  
Magnetic Moments ◽  
Nearest Neighbors ◽  
Field Energy ◽  
Zero Field ◽  
Heisenberg Exchange ◽  
Neighbor Effect

The Next Nearest Neighbor (NNN) effect in Ni 2+-[2×2] using the isotropic Heisenberg model has been investigated in this article. Although the NNN effect is commonly very weak in this kind of grid, it was calculated that its response is quite big to the outsider perturbations in certain regions. Two different antiferromagnetic arrangements of spins interacting via the Heisenberg exchange type in a square were discussed in terms of their stability regions. Using the isotropic Heisenberg exchange Hamiltonian, the zero field energy spectrum has been calculated for this particular Ni 2+-[2×2] grid geometry. The average magnetic moments with and without the next nearest neighbors interactions were also calculated. In order to verify the calculations, the results were compared with experimental data which had been published in literature.

The role of initial and final states in molecular spectroscopies

2019 ◽  
Vol 21 (24) ◽  
pp. 12730-12747 ◽  
Author(s):  
Tino Kirchhuebel ◽  
Oliver L. A. Monti ◽  
Toshiaki Munakata ◽  
Satoshi Kera ◽  
Roman Forker ◽  
...  
Keyword(s):  
Experimental Data ◽  
Thin Films ◽  
Organic Semiconductors ◽  
Careful Consideration ◽  
Spectroscopic Techniques ◽  
Final States ◽  
The Relationship

Interpreting experimental spectra of thin films of organic semiconductors is challenging, and understanding the relationship between experimental data obtained by different spectroscopic techniques requires a careful consideration of the initial and final states for each process.

Application of Bogoliubov-de Gennes equations to vortices in Hubbard superconductors

2015 ◽  
Vol 1753 ◽  
Author(s):  
Chumin Wang ◽  
César G. Galván ◽  
Luis A. Pérez
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Electron Concentration ◽  
Nearest Neighbor ◽  
Magnetic Vortex ◽  
Superconducting Gap ◽  
Electronic Specific Heat ◽  
Neighbor Interaction ◽  
Self Consistent ◽  
Generalized Hubbard Model

ABSTRACTIn this work, the formation of d-wave superconducting magnetic vortex is studied within the Bogoliubov-de Gennes formalism and the generalized Hubbard model, which leads to 2N2 coupled self-consistent equations for a supercell of N×N atoms. These equations determine the spatial variation of the superconducting gap as a function of the electron concentration and electron-electron interactions. The results show that the superconducting states induced by the correlated hopping (Δt3) are more sensitive to the presence of magnetic field than those induced by attractive nearest-neighbor interaction (V). Furthermore, we calculate the electronic specific heat as a function of the temperature for a given applied magnetic field, whose behavior has a qualitative agreement with experimental data.

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