Monte Carlo Simulations of Growth Kinetics and Phase Transitions at Interfaces: Some Recent Results

1991 ◽  
Vol 237 ◽  
Author(s):  
P. Nielaba ◽  
K. Binder
Keyword(s):  
Monte Carlo ◽  
Phase Transitions ◽  
Fluid Layer ◽  
Finite Size ◽  
Critical Temperatures ◽  
Infinite Layer ◽  
Limit Value ◽  
Monte Carlo Studies ◽  
Coexistence Densities ◽  
Kinetics Of

ABSTRACTIn the first part Monte Carlo studies of the kinetics of multilayer adsorption (without screening) are described. The approach to the jamming coverage in each layer is asymptotically exponential. The jamming coverages approach the infinite-layer limit value according to a power law. In the second part, studies of phase transitions in two dimensional fluids are reviewed. With a combination of Monte Carlo and finite size scaling block analysis techniques, accurate values are obtained for the critical temperatures, coexistence densities and the compressibilities of an adsorbed fluid layer in an NVT ensemble.

Kinetics of B2, DO3, and B32 ordering: Results from pair approximation calculations and Monte Carlo simulations

1994 ◽  
Vol 9 (2) ◽  
pp. 348-356 ◽  
Author(s):  
L. Anthony ◽  
B. Fultz
Keyword(s):  
Monte Carlo ◽  
Kinetic Theory ◽  
Monte Carlo Simulations ◽  
Nearest Neighbor ◽  
Pair Approximation ◽  
Probability Method ◽  
Critical Temperatures ◽  
Point Pair ◽  
Bcc Lattice ◽  
Kinetics Of

A kinetic theory of ordering based on the path probability method was implemented in the pair (Bethe) approximation and used to study the kinetics of short- and long-range ordering in alloys with equilibrium states of B2, DO3, or B32 order. The theory was developed in a superposition approximation for a vacancy mechanism on a bcc lattice with first- (1nn) and second-nearest neighbor (2nn) pair interactions. Chained 1nn conditional probabilities were used to account for the entropy of 2nn pair configurations. Monte Carlo simulations of ordering were also performed and their results compared to predictions of the pair approximation. Comparisons are also made with predictions from an earlier kinetic theory implemented in the point (Bragg-Williams) approximation. For all three calculations (point, pair, and Monte Carlo), critical temperatures for B2 and DO3 ordering are reported for different 1nn and 2nn interaction strengths. The influence of annealing temperature on the kinetic paths through the space of B2, DO3, and B32 order parameters was found to be strong when the thermodynamic preferences for the ordered states were of similar strengths. Transient states of intermediate order were also studied. A transient formation of B32 order in an AB3 alloy was found when 2nn interactions were strong, even when B32 order was neither a Richards-Allen-Cahn ground state nor a stable equilibrium state at that temperature. The formation of this transient B32 order can be argued consistently from a thermodynamic perspective. However, a second example of transient B2 order in an AB alloy with equilibrium B32 order cannot be explained by the same thermodynamic argument, and we believe that its origin is primarily kinetic.

MONTE CARLO STUDY OF MULTILAYER FILMS USING ANISOTROPIC EXTENDED HEISENBERG MODEL WITH DIPOLAR INTERACTION

2009 ◽  
Vol 23 (04) ◽  
pp. 643-653 ◽  
Author(s):  
E. BÎRSAN ◽  
A. DOBRITA ◽  
R. CHIS
Keyword(s):  
Monte Carlo ◽  
Phase Transitions ◽  
Basal Layer ◽  
Magnetic Ordering ◽  
Monte Carlo Study ◽  
Magnetic Phase Transitions ◽  
Physical Parameters ◽  
Critical Temperatures ◽  
Two Phase ◽  
Antiferromagnetic Ordering

Using the Monte Carlo technique, we study the multilayer Heisenberg thin film with long range dipolar interactions, in order to investigate the antiferromagnetic basal layer influence on the superior layers. We find out that the basal layer's influence over the magnetic ordering of the superior layers is dependent on the distance between that layer and the basal layer, and the exchange anisotropy discontinuity has a direct effect on the critical temperatures associated with the magnetic phase transitions that can occur for different settings of the investigated system physical parameters. In the intermediate dipolar parameter region, due to antiferromagnetic ordering of the basal layer spins, we found out the mixed phase appearance in the superior layers and we relieved two phase transitions which can take place in the system, the critical temperature we obtained by studying the specific heat and the magnetic susceptibility, respectively, being in good agreement.

MONTE CARLO APPROACH ON DOUBLE-LAYER MAGNETIC SPIN LATTICE IN ANISOTROPIC HEISENBERG MODEL

2009 ◽  
Vol 23 (02) ◽  
pp. 251-264
Author(s):  
EUGEN BÎRSAN ◽  
OLIVIAN NIGA
Keyword(s):  
Monte Carlo ◽  
Double Layer ◽  
Heisenberg Model ◽  
Finite Size ◽  
Finite Size Effect ◽  
Parameter Distribution ◽  
Physical Parameters ◽  
Model Parameters ◽  
Critical Temperatures ◽  
Anisotropic Heisenberg Model

In this paper, we investigate the magnetic properties of double-layer thin film using Monte Carlo technique, in anisotropic Heisenberg model. The magnetization, out-of-plane and in-plane magnetic susceptibilities, and also the specific heat behaviors according to temperature are investigated in order to find out the contingent magnetic ordering phases and the critical temperatures values, for two easy-axis anisotropy parameters settings. We also calculate the relative variation rate of the critical temperature along with the easy-plane anisotropy interaction parameter distribution, and we comparatively appraise the numerical obtained results, in order to get quantitative response on the physical model parameters changes. Finally, we present a finite size effect study on magnetic susceptibility, respecting the two settings physical parameters we assumed in the paper.

Monte Carlo studies of finite-size effects at first-order transitions

1990 ◽  
Vol 24-26 (1) ◽  
pp. 343-369 ◽  
Author(s):  
M. S. S. Challa ◽  
D. P. Landau ◽  
K. Binder
Keyword(s):  
Monte Carlo ◽  
Size Effects ◽  
Finite Size ◽  
Finite Size Effects ◽  
First Order ◽  
Monte Carlo Studies
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