Critical behavior of Pr0.65Sr0.35MnO3 compound investigated by a Monte Carlo simulation

Author(s):  
Lhaj el Hachemi Omari ◽  
Abdelmajid Lekdadri ◽  
Rachid Chami ◽  
El Kibir Hlil

The critical behavior and magnetic properties of Pr0.65Sr0.35MnO3 (symbolized by PSMO) were studied using Monte Carlo simulation (MCS). The thermal bath algorithm and the Ising model in which exchange interactions via the third nearest neighbor were used to calculate the magnetic and magneto-caloric properties. The effects of temperature (T) and external magnetic field (h) on the magnetic behavior of PSMO were examined. The results show that the Curie temperature (TC) is close to the experimental value. The magnetic entropy shows a maximum value around the TC which increases linearly with the increase of the external field. The expected critical behavior of the PSMO nanoparticles was studied through the isothermal magnetization and from the Arrott plots. The obtained values are β = 0.356, γ = 1.121, and δ = 3.95. These values not so far from those reported for the 3D-Ising model. The variation of maximum magnetic entropy (∆S_m^max) and relative cooling power (RCP) around the Curie temperature were calculated; the resulting values of ∆S_m^max and those of RCP range from 3.612 and 92.7 for 1T to 6.191 and 209.9 for 5T, respectively. These results are sufficiently interesting to consider the PSMO compound as a promising candidate for magnetic refrigeration.

2016 ◽  
Vol 845 ◽  
pp. 150-153
Author(s):  
Andrey N. Vakilov

We used a Monte Carlo simulation of the structurally disordered three dimensional Ising model. For the systems with spin concentrations p = 0.95 ,0.8, 0.6 and 0.5 we calculated the correlation-length critical exponent ν by finite-size scaling. Extrapolations to the thermodynamic limit yield ν(0.95) = 0.705(5) ,ν(0.8) = 0.711(6),ν(0.6) = 0.736(6) and ν(0.5) = 0.744(6). These results are compatible with some previous estimates from a variety of sources. The analysis of the results demonstrates the nonuniversality of the critical behavior in the disordered Ising model.


2014 ◽  
Vol 6 (1) ◽  
pp. 119-129
Author(s):  
Eugenii Anatolievich Pospelov ◽  
Pavel Vladimirovich Prudnikov ◽  
Vladimir Vasilievich Prudnikov

Author(s):  
Subir K Das ◽  
Nalina Vadakkayil

For quicker formation of ice, before inserting inside a refrigerator, heating up of a body of water can be beneficial. We report first observation of a counterpart of this intriguing...


1994 ◽  
Vol 05 (03) ◽  
pp. 513-518 ◽  
Author(s):  
DIETRICH STAUFFER

The high-dimensional shape space for the antibodies of the immune system is simulated with an Ising-like interaction. However, instead of the molecular field being linear in the sum of the neighbor spins, we take it as quadratic and negative. In this way the bell-shaped response curve of biological immune systems is approximated, as a probabilistic generalization of window automata. We find phase transitions only in five and more dimensions, not in two to four, for nearest-neighbor interactions.


2007 ◽  
Vol 558-559 ◽  
pp. 1057-1061 ◽  
Author(s):  
Abhijit P. Brahme ◽  
Joseph M. Fridy ◽  
Anthony D. Rollett

A model has been constructed for the microstructural evolution that occurs during the annealing of aluminum alloys. Geometric and crystallographic observations from two orthogonal sections through a polycrystal using automated Electron Back-Scatter Diffraction (EBSD) were used as an input to the computer simulations to create a statistically representative threedimensional model. The microstructure is generated using a voxel-based tessellation technique. Assignment of orientations to the grains is controlled to ensure that both texture and nearest neighbor relationships match the observed distributions. The microstructures thus obtained are allowed to evolve using a Monte-Carlo simulation. Anisotropic grain boundary properties are used in the simulations. Nucleation is done in accordance with experimental observations on the likelihood of occurrences in particular neighborhoods. We will present the effect of temperature on the model predictions.


2005 ◽  
Vol 16 (04) ◽  
pp. 585-589 ◽  
Author(s):  
MUNEER A. SUMOUR ◽  
M. M. SHABAT

The existence of spontaneous magnetization of Ising spins on directed Barabasi–Albert networks is investigated with seven neighbors, by using Monte Carlo simulations. In large systems, we see the magnetization for different temperatures T to decay after a characteristic time τ(T), which is extrapolated to diverge at zero temperature.


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