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Using Monte Carlo simulations under the Metropolis algorithm, the magnetic properties of a Mixed Spins (3/2, 1) cubic lattice modeled by mixed spin Ising model have been investigated. First, we discuss the ground state phase diagrams at zero temperature corresponding to different parameters of the model. Then, by choosing ferrimagnetic phases found in the obtained phase diagrams, we analyze the magnetization and compensation behaviors in our system. Striking results have been found; especially, the competition between exchange coupling interactions generates a critical temperature T C and a compensation temperature T comp with T comp < T C . Moreover, the presence of crystal and external magnetic fields leads to the appearance of a second compensation temperature with T c o m p 1 < T c o m p 2 ≪ T C . [ABSTRACT FROM AUTHOR]

A spin-1/2, Ising trilayered ferrimagnetic system on square Bravais lattice is studied, employing Monte-Carlo simulation with the single spin-flip Metropolis algorithm. The bulk of such a system is formed by three layers, each of which is composed entirely either by A or B type of atoms, resulting in two distinct compositions: ABA and AAB and two different types of magnetic interactions: ferromagnetic between like atoms and antiferromagnetic between unlike atoms. For such systems, Inverse Absolute of Reduced Residual Magnetisation is the absolute value of the ratio of the extremum of the magnetisation in between compensation and critical points and the saturation magnetisation. Variation of relative interaction strengths in the Hamiltonian, for a range of values, leads to the shift of compensation point and critical point and changes in the magnitude of inverse absolute of reduced residual magnetisation. Probable mathematical forms of dependences of the inverse absolute of reduced residual magnetisation and temperature interval between the critical and compensation temperatures on controlling parameters are proposed in the absence of applied magnetic field and have obtained phase diagrams for both types of configurations from these relations. This alternative description of the simulated systems may help technologists design magnetocaloric materials according to desired characteristics. [ABSTRACT FROM AUTHOR]

We have employed first-principles calculations of density functional theory (DFT) with GGA and GGA+U exchange correlation to study structural, magnetic, and electronic properties of chromium nitride (CrN) in the rock salt (NaCl) structures. The obtained data from DFT calculations is used as an input in high-temperature series expansions (HTSEs) combined with the Padé approximants (PA) method and Monte Carlo simulation (MC) for the Ising model to investigate the magnetic properties of CrN. The obtained results show that CrN is more stable in the antiferromagnetic order, and undergoes structural and magnetic transitions from an antiferromagnetic NaCl structure to a nonmagnetic Pnma phase at 201 GPa. The density of states (DOS) with GGA approach shows that CrN has a metallic behavior in both FM and AFM configurations whereas with GGA+U CrN is semiconductor in AFM and half-metallic in FM order. The Neel temperature (TN) obtained by HTSE and MC is in agreement with available experimental data. [ABSTRACT FROM AUTHOR]

The structural, electronic, and magnetic properties of the NiFe2O4 compound are studied using several theoretical methods such as first-principle calculations based on density functional theory (DFT), Monte Carlo simulations, and mean-field theory. The exchange-correlation potential was resolved by generalized gradient approximation (GGA) that underestimates the band gap energy value; therefore, this later needed to be corrected using the GGA + U approximation. The gap energy value (1.10 eV) obtained by the theoretical method is in good agreement with experimental value (0.99 eV). Using ab initio calculations, the exchange-coupling interactions are J1 = 40.665 meV, J2 = 45.382 meV, and J3 = −3.260 meV. Moreover, the semiconductor NiFe2O4 compound exhibits a second-order ferromagnetic-paramagnetic phase transition around TC = 844 K; this value is in good agreement with experimental results. The total magnetization, susceptibility, and specific heat of this compound are investigated. [ABSTRACT FROM AUTHOR]

In this paper, we have studied the structural, electronic, and magnetic properties of the cubic perovskite system Mn4N using the first principles calculations based on density functional theory (DFT) with the generalized gradient approximation (GGA). The obtained data from DFT calculations are used as input data in Monte Carlo simulation with a mixed spin-5/2 and 1 Ising model to calculate the magnetic properties of this compound, such as the total, partial thermal magnetization, and the critical temperatures (TC). The obtained results show that Mn4N has a ferrimagnetic structure with two different sites of Mn in the lattice and presents a metallic behavior. The obtained TC is in good agreement with experimental results. [ABSTRACT FROM AUTHOR]

In the presence of the crystal field D/JCore and the external magnetic field h/JCore, using the Monte Carlo (MC) simulation based on the heat bath algorithm and the effective field theory (EFT), the triangular mixed spin nanowire model consisting of a spin-(1/2) core which is encircled by a spin-1 ferrimagnetic surface shell is studied. We have studied the special effects of the core surface and crystal field on the critical and compensation temperatures. Several properties, such as the magnetization, hysteresis behaviors, coercive field, and remanent magnetizations are studied. For the appropriate values of the system parameters, the compensation point and multi-loops are found PACS 05.50. + q; 77.80. Bh. [ABSTRACT FROM AUTHOR]

The XY model has been used in a centered rectangular lattice structure consists of two sub-lattices of spin 1–1/2 with different ferromagnetic couplings on each lattice and anti-ferromagnetic interaction between the two sub-lattices. Utilizing the Monte Carlo simulation, we have studied the energy per site, the specific heat, the total magnetization, the initial susceptibility, and hysteresis effects. Our results revealed that existences of two peaks on the specific heat and a single loop historic behavior. The Binder cumulant and initial susceptibility both confirmed the existence of critical temperature where the system possesses a phase transition to paramagnetism. Such behaviors are monitoring by the different coupling constants adopted in this study. [ABSTRACT FROM AUTHOR]

The magnetic properties of mixed-spin S = 3/2 and S = 1/2 ferrimagnetic system have been studied by Monte Carlo simulations. The ground-state phase diagrams of mixed spin-3/2 and spin-1/2 Ising system are given. The critical and compensation temperatures have been found with different values of reduced exchange interactions. The variation of total magnetization with reduced exchange interactions of mixed spins is given with different temperatures and crystal fields. We have also given the variation of total magnetization with crystal field for different reduced exchange interactions and different temperatures. The magnetic hysteresis cycle is found to have different values of reduced exchange interactions, temperatures, and crystal fields. The multiple hysteresis and the superparamagnetic phase are established. [ABSTRACT FROM AUTHOR]

The magnetic properties of Ising nanoisland with a ferrimagnetic spin-1 and 3/2 configuration are studied by Monte Carlo simulation. The ground state phase diagrams of mixed spins are obtained. The critical temperature is obtained for different values of exchange interactions and for different crystal fields. The magnetic hysteresis cycle is obtained with different values of temperature, exchange interactions, and crystal field values. The applications of the Monte Carlo to the magnetic properties are extremely restricted for nanoislands, when the value of an interlayer coupling takes a large value, in contrast to a number of bulk studies. [ABSTRACT FROM AUTHOR]

A Monte Carlo simulation based on Metropolis algorithm has been used to investigate the magnetic properties of an Ising ferrimagnetic nanowire on a hexagonal structure, which is made up with L alternate layers of spins σ = ±3/2, ±1/2 and S = ±1, 0. The critical behaviors are studied, in the absence as well as in the presence of crystal field interactions. The obtained results show the existence of some interesting phenomena, such as the appearance of different types of phase diagrams. Furthermore, tricritical point, isolated critical point, critical end point, and compensation behavior are found for appropriate values of the system parameters. [ABSTRACT FROM AUTHOR]