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.

scholarly journals Antiferromagnetic and ferromagnetic spintronics and the role of in-chain and inter-chain interaction on spin transport in the Heisenberg ferromagnet

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
L. S. Lima
Keyword(s):  
Spin Transport ◽  
Nearest Neighbor ◽  
Heisenberg Ferromagnet ◽  
Spin Correlations ◽  
Ferromagnetic Domain ◽  
Frustrated Spin ◽  
Ferromagnetic Domain Wall ◽  
Chain Interaction ◽  
The Continuum

AbstractSpin-transport and current-induced torques in ferromagnet heterostructures given by a ferromagnetic domain wall are investigated. Furthermore, the continuum spin conductivity is studied in a frustrated spin system given by the Heisenberg model with ferromagnetic in-chain interaction $$J_1<0$$ J 1 < 0 between nearest neighbors and antiferromagnetic next-nearest-neighbor in-chain interaction $$J_2>0$$ J 2 > 0 with aim to investigate the effect of the phase diagram of the critical ion single anisotropy $$D_c$$ D c as a function of $$J_2$$ 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 $$J_{\perp ,y}$$ J ⊥ , y and $$J_{\perp ,z}$$ J ⊥ , z , corresponding to the two axes perpendicular to chain where ferromagnetic as well as antiferromagnetic interactions are taken into account.

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.

Ising Antiferromagnet with Nearest-Neighbor and Next-Nearest-Neighbor Interactions on a Square Lattice

2014 ◽  
Vol 215 ◽  
pp. 17-21
Author(s):  
Akai K. Murtazaev ◽  
Magomedsheikh K. Ramazanov ◽  
Magomedzagir K. Badiev
Keyword(s):  
Nearest Neighbor ◽  
Finite Size ◽  
Nearest Neighbors ◽  
Correlation Radius ◽  
Square Lattice ◽  
Two Dimensional ◽  
Critical Properties ◽  
Finite Size Scaling ◽  
Ising Antiferromagnet ◽  
Antiferromagnetic Ising Model

The critical properties of two-dimensional antiferromagnetic Ising model in square lattice are investigated using the replica Monte-Carlo method with account of interactions of second nearest neighbors. The diagram of critical temperature dependence on an interaction value of second nearest neighbors is plotted. Static critical exponents of the heat capacity α, susceptibility γ, magnetization β, and correlation radius ν are calculated for this model using the finite-size scaling theory.

scholarly journals Phase transition and monopole densities in a nearest neighbor two-dimensional spin ice model

2017 ◽  
Vol 31 (31) ◽  
pp. 1750237
Author(s):  
C. W. Morais ◽  
D. N. De Freitas ◽  
A. L. Mota ◽  
E. C. Bastone
Keyword(s):  
Phase Transition ◽  
Long Range ◽  
Ground State ◽  
Nearest Neighbor ◽  
Nearest Neighbors ◽  
Dipolar Interaction ◽  
Effective Model ◽  
Two Dimensional ◽  
Spin Ice ◽  
Ice Model

In this work, we show that, due to the alternating orientation of the spins in the ground state of the artificial square spin ice, the influence of a set of spins at a certain distance of a reference spin decreases faster than the expected result for the long range dipolar interaction, justifying the use of the nearest neighbor two-dimensional square spin ice model as an effective model. Using an extension of the model presented in Y. L. Xie et al., Sci. Rep. 5, 15875 (2015), considering the influence of the eight nearest neighbors of each spin on the lattice, we analyze the thermodynamics of the model and study the dependence of monopoles and string densities as a function of the temperature.

scholarly journals NEAR-BOUNDARY AND BULK REGIONS OF A SEMI-INFINITE TWO-DIMENSIONAL HEISENBERG ANTIFERROMAGNET

2010 ◽  
Vol 24 (22) ◽  
pp. 2327-2334 ◽  
Author(s):  
N. VOROPAJEVA ◽  
A. SHERMAN
Keyword(s):  
Spin Wave ◽  
Nearest Neighbor ◽  
Spin Waves ◽  
Two Dimensional ◽  
Heisenberg Antiferromagnet ◽  
Elementary Excitations ◽  
Spin Correlations ◽  
One Dimensional ◽  
Wave Approximation

Using the spin-wave approximation elementary excitations of a semi-infinite two-dimensional S = ½ Heisenberg antiferromagnet are considered. The spectrum consists of bulk modes — standing spin waves and a quasi-one-dimensional mode of boundary spin waves. These latter excitations eject bulk modes from two boundary rows of sites, thereby dividing the antiferromagnet into two regions with different dominant excitations. As a result, absolute values of nearest-neighbor spin correlations on the edge exceed the bulk value.

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.

Observation of Superlattice Dislocations on Cube Planes in Ni3Al

1973 ◽  
Vol 31 ◽  
pp. 174-175 ◽  
Author(s):  
J. M. Oblak ◽  
W. H. Rand
Keyword(s):  
Nearest Neighbor ◽  
Antiphase Boundary ◽  
Nearest Neighbors ◽  
High Energy ◽  
Cross Slip ◽  
Octahedral Plane ◽  
Trapping Mechanism ◽  
Slip Traces

The energy of an a/2 <110> shear antiphase. boundary in the Ll2 expected to be at a minimum on {100} cube planes because here strue ture is there is no violation of nearest-neighbor order. The latter however does involve the disruption of second nearest neighbors. It has been suggested that cross slip of paired a/2 <110> dislocations from octahedral onto cube planes is an important dislocation trapping mechanism in Ni3Al; furthermore, slip traces consistent with cube slip are observed above 920°K.Due to the high energy of the {111} antiphase boundary (> 200 mJ/m2), paired a/2 <110> dislocations are tightly constricted on the octahedral plane and cannot be individually resolved.

Temporal Changes in Habitat Selection and Nest Spacing in a Colony of Ross' and Lesser Snow Geese

The Auk ◽  
1983 ◽  
Vol 100 (2) ◽  
pp. 335-343 ◽  
Author(s):  
M. Robert McLandress
Keyword(s):  
Nearest Neighbor ◽  
Average Distance ◽  
Habitat Preferences ◽  
Nearest Neighbors ◽  
Nest Density ◽  
Snow Goose ◽  
Snow Geese ◽  
Lesser Snow Geese ◽  
Average Size ◽  
Island Habitats

Abstract I studied the nesting colony of Ross' Geese (Chen rossii) and Lesser Snow Geese (C. caerulescens caerulescens) at Karrak Lake in the central Arctic of Canada in the summer of 1976. Related studies indicated that this colony had grown from 18,000 birds in 1966-1968 to 54,500 birds in 1976. In 1976, geese nested on islands that were used in the late 1960's and on an island and mainland sites that were previously unoccupied. Average nest density in 1976 was three-fold greater than in the late 1960's. Consequently, the average distance to nearest neighbors of Ross' Geese in 1976 was half the average distance determined 10 yr earlier. The mean clutch size of Ross' Geese was greater in island habitats where nest densities were high than in less populated island or mainland habitats. The average size of Snow Goose clutches did not differ significantly among island habitats but was larger at island than at mainland sites. Large clutches were most likely attributable to older and/or earlier nesting females. Habitat preferences apparently differed between species. Small clutches presumably indicated that young geese nested in areas where nest densities were low. The establishment of mainland nesting at Karrak Lake probably began with young Snow Geese using peripheral areas of the colony. Young Ross' Geese nested in sparsely populated habitats on islands to a greater extent than did Snow Geese. Ross' Geese also nested on the mainland but in lower densities than Ross' Geese nesting in similar island habitats. Successful nests with the larger clutches had closer conspecific neighbors than did successful nests with smaller clutches. The species composition of nearest neighbors changed significantly with distance from Snow Goose nests but not Ross' Goose nests. Nesting success was not affected by the species of nearest neighbor, however. Because they have complementary antipredator adaptations, Ross' and Snow geese may benefit by nesting together.

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