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One of the most active classes of nanostructures is Fullerene C$_{20}$, which has been exploited as an active component in significant applications. In this investigation, we used Monte Carlo simulations to investigate the magnetic and magnetocaloric properties of the mixed spins 2 and 3/2 Fullerene C$_{20}$ system. Ferrimagnetic and ferromagnetic phases are stable, according to the ground state phase diagrams that have been constructed. The behavior of the magnetizations and the derivative of magnetization, in particular, have shown the impact of rising temperature. Additionally, we found an increase of the reduced Curie temperature to reach $t_C = 3$, when the interactions between the spins S are increased. For numerous reduced external magnetic fields and reduced temperatures, the magnetic entropy variations are studied. The Relative Cooling Power (RCP) is calculated. It is demonstrated that the reduced exchange coupling interactions p and r lead to an increase in the lowered magnetic coercive field.

In the present work, we study the structural, electronic and optical properties of Sodium Based Cubic Fluoro-perovskites: NaBF$_3$ (B= Ca, Mg or Zn) using DFT and TDDFT methods. We performed the density functional theory DFT calculations under the mBJ-GGA approximation. In addition, we applied the norm-conserving pseudo-potentials without spin-orbit coupling (SOC) approximations. In addition, we used the Perdew-Burke-Ernzerhof generalized gradient approximation (GGA-PBE) to deduce the physical properties of these alloys. Moreover, the Time-Dependent Density Functional Theory (TDDFT) method has been performed to deduce the optical properties, in an excited state, of the studied Sodium Based Cubic Fluoro-perovskites: NaBF$_3$ (B= Ca, Mg or Zn) materials.

To investigate the physical characteristics of the half-Heusler BaHgSn molecule, we used theoretical calculations within the Density Functional Theory (DFT) framework utilizing the LSDA+mBJ technique in this study. Using the optimal lattice parameters, we discover that half-Heusler BaHgSn exhibits a Dirac semimetal behavior with a band gap of 0.1 eV. Thomas Charpin's numerical first-principles calculation approach was applied to determine the elastic constants of hexagonal BaHgSn alloys. The material's optical characteristics verified its prospective use in infrared-visible devices. According to a thermo-electric properties analysis, at 20x10^18 {\Omega}-1.m-1.s-1, the electrical conductivity reaches its maximum after increasing gradually up to 500 K. Compared to other compounds, these results indicate that BaHgSn has potential for use in opto-electronic and thermo-electric devices.

In this study, we investigate the electronic, optical, thermoelectric, and thermodynamic properties of Ca(InP)2 through comprehensive theoretical calculations Ca(InP)2 is a compound with promising applications in materials science and electronics. Using the density functional theory (DFT) with Generalized Gradient Approximation (GGA) and modified Becke_Johnson approximation (mBJ), we determine the band structure, density of states, and optical properties of Ca(InP)2. The obtained results reveal that the Ca(InP)2 compound exhibits a direct band gap of 0 eV and 0,645 eV for PBE-GGA and GGA+mBJ, respectively. This direct band gap is found at the Gamma point of the Brillouin zone, making it well-suited for optoelectronic applications. Furthermore, we analyze the thermoelectric properties such as the Seebeck coefficient, the lattice thermal conductivity, and optical properties like dielectric function, absorption coefficient, conductivity, and extinction coefficient. Thermodynamic properties, including heat capacity and Debye temperature, are also calculated, providing a deeper understanding of the compound's thermal behavior. The findings of this study highlight the fundamental characteristics of Ca(InP)2 and offer valuable information for its potential use in electronic and optoelectronic devices. A comprehensive understanding of the electronic, optical, and thermodynamic properties of the Ca(InP)2 compound can serve as a guide for future experimental research and aid in the design of novel materials for a wide range of technological applications.

In this work, we used the density functional calculation (DFT) implemented in the Quantum Espresso software, using the approximations (GGA, GGA+U) to illustrate the electronic and magnetic properties of the perovskite CaMnO$_3$. It has been found that the CaMnO$_3$ perovskite is stable in the G-AFM phase. When expecting the total and partial DOSs, a strong contribution of the d-Mn states has been outlined. The Coulomb correction U and the site exchange interaction J have been implemented and then we compared the two approximations GGA and GGA+U. It is found that the GGA+U method leads to more accurate results since this correction takes into account the bonding effects between different atoms. To complete this study we performed the simulations under Monte Carlo code based on the Metropolis algorithm. In fact, we have simulated the physical quantities: magnetization, susceptibility, and specific heat of the studied CaMnO$_3$ material as a function of temperature.

In this article, we examine the structure and the electronic, optical, and magnetic properties of ZnTe before and after doping with the transition metal Mn. The ab initio calculations of this compound were performed using the full potential linearized extended full potential planar waveform (FP-LAPW) in the context of density functional theory (DFT) implemented in the Wien2K code. The potential for exchange and correlation was addressed by the generalized gradient approximation (GGA) approximation. The electronic properties show that the ZnTe material exhibits semiconductor behavior before doping. As a result, it becomes semimetal after doping. The findings attained by Monte Carlo simulations display that the ZnMnTe material goes from an antiferromagnetic phase to the paramagnetic phase at the Neel temperature value TN =159.31 K.

In this study, we carried out an investigation of the EuCoA$_2$As$_2$ compound, focusing on its various physical properties. Our analysis covered the structural, magnetic, electronic, optical, thermodynamic and thermoelectric characteristics of this compound. To carry out this study, we used density functional theory (DFT) implemented in the Wien2k software package. To determine the exchange-correlation potential, we used the GGA-PBE (Perdew, Burke and Ernzerhof) approach, taking spin-orbit coupling (SOC) into account. Our results indicate that the EuCoA$_2$As$_2$ compound exhibits metallic behavior. In addition, we have determined that the compound's stable ground state is the ferromagnetic (FM) phase. We have also calculated the Debye temperature and the Gr\"uneisen parameter. In addition, we evaluated various optical properties, including electron energy loss, absorption coefficient, real and imaginary dielectric tensors, and real and imaginary optical conductivity. We found that the compound has excellent absorption characteristics in the low and mid ultraviolet (UV) spectra. In addition, we investigated the electrical conductivity, Seebeck coefficient, electronic conductivity and thermal conductivity of the lattice. The results revealed that the compound exhibits n-type behavior, with negative values for the Seebeck coefficient. These results are analyzed in detail and provide valuable information on the properties of the EuCoA$_2$As$_2$ compound. Additionally, the computed parameters were compared to those found in the literature. A good deals have been revealed with the existing results., Comment: 26 pages, 7 figures, 3 tables

Using the density functional theory (DFT) in combination with Boltzmann transport theory, the influence of Mg concentrations (x) doping on the thermoelectric properties of Hg1-xMgxSe ternary alloys was systematically investigated. The generalized gradient approximations of Perdew-Burke-Ernzerhof (GGA-PBE) have been used to illustrate the exchange correlation potential. Various thermoelectric transport parameters, such as the Seebeck coefficient (S), the thermal conductivity over relaxation time, the electrical conductivity over relaxation time, the power factor (PF) and the figure of merit (ZT) have been deduced and discussed. The obtained results of thermoelectric properties show that the studied materials can be useful for room temperature thermoelectric devices. It is also found that Mg compositions can increase the thermal efficiency of the HgSe alloy.

In this paper, we have focused on a comparison of the different magnetic properties of the three nano-Heusler Ru$_2$Mn$_X$ (X = Nb, Ta or V) compounds using the Blume-Capel Ising model. The Heusler structures are composed by different mixed spins. In fact, the Ru and Mn atoms are modeled by spin-5/2 and spin-1/2, respectively. While, the X atoms ($X$ = Nb, Ta and V) are represented by the spin-7/2, spin-3/2 and spin-5/2, respectively. This study is carried out by using the Monte Carlo simulations under the Metropolis algorithm. The magnetic behaviors of the three nano-Heusler compounds have been studied and discussed. It is found that Ferrimagnetic to superparamagnetic transitions were observed corresponding to different blocking temperatures. Besides, the effect of the crystal field, the exchange coupling interactions and the external magnetic field have been inspected on the magnetization of each nano-Heusler compound Ru$_2$Mn$_X$ ($X$ = Nb, Ta or V).

This paper concerns the investigation of the critical (HC) and the saturation (HS) magnetic fields behavior of the studied system as a function of different physical parameters. The Monte Carlo method has been used to study the magnetic properties of a ferrimagnetic behavior of a double fullerene X60 core/shell like-nanostructure, where the symbol X can be assigned to any magnetic atom. Based on the Ising model, we focus our study on a system formed by a double sphere core/shell. The two spheres are containing the spins: $\sigma=\pm 1/2$ in the core are surrounded by the spin $S=\pm 1, 0$ in the shell. Many types of magnetization curves have been found, depending on the competitions among the exchange couplings, the crystal fields and the temperature.

In this paper, we study the critical magnetic properties of the Half Heusler alloy RhCrSi, using Monte Carlo simulations (MCS) under the Metropolis algorithm. In fact, to study this alloy, we apply an Ising model using the MCS simulations, we concentrate only on the magnetic atoms: Rh and Cr. For this purpose, these magnetic atoms are modeled by the spin moments S=5/2 for Rh atoms and sigma=2 for Cr atoms, respectively. In addition, we discuss the ground state phase diagrams in different planes corresponding to different physical parameters. On the other hand, for non-null temperature values, we perform the Monte Carlo simulations (MCS) to study the critical behavior of the compound RhCrSi, in the Ising approximation. Indeed, we present a detailed discussion of the obtained results for the magnetizations as a function of the temperature, the crystal field and the exchange coupling interactions. Additionally, we give the reliance of the basic temperature as an element of precious crystal field when fixing the exchange coupling interactions. To finish this work, we built up and examined the magnetic hysteresis cycles and the relating coercive fields as a part of the external magnetic field.

In this work, we study the equiatomic quaternary Heusler Alloy CoFeCrP using two methods: DFT and Monte Carlo simulations. The DFT method allowed us to illustrate the structural, electronic and magnetic properties of this alloy. The ground state phase diagrams have been presented to show the stable configurations in different physical parameter planes. On the other hand, the Monte Carlo simulations, performed under the Metropolis algorithm, permitted to deduce the critical the behavior of the equiatomic quaternary Heusler alloy CoFeCrP. The structural properties results show that the phase of type I, of this alloy is the most stable configuration. In addition, the band structures, and density of states calculations results show that this compound exhibits a half-metallic character with a 100 % of spin polarization (SP) at the Fermi-level. The total magnetic moment of the Heusler compound is found to be 4.00 mu_B. Moreover, it is found that the Slater-Pauling is well described for this alloy. Our results show that this material is a potential candidate for the spintronic applications. This is due to its half-metallicity, its high spin moments, its complete SP polarization and its high Curie temperature.

In this work, we study the effect of doping the Rutile-type dioxide SnO2 material by the non-metal Sulfur (S) atoms on the electronic properties. In fact, we have used the ab-initio method applied on the basis of the Density Functional Theory (DFT) using the Quantum Espresso code. Through the density of states and the band structure calculations for different concentrations have been deduced. When doping the SnO2 material with 6% of Sulfur (S), we found a perfect symmetry between up and down spin states in the total DOS confirming the non-magnetic behavior of this material doped SnO2 with 6% of Sulfur. It is also worth to note that the SnO2 material doped with 6% of Sulfur, exhibits a semiconductor of the P-type. Moreover the band gap decreases when increasing the concentration of doping the SnO2 by Sulfur. Our results are in good agreement with the existing literature both experimental and theoretical.

Using Monte Carlo Simulations (MCS), based the Metropolis algorithm, we examine in this study, the magnetic properties of the rare earth based compound GdN. In a first step, we discuss and study the ground state phase diagrams explored in the different planes of physical parameter. The obtained stable configurations are illustrated by comparing the energies modeled by the Hamiltonian of Eq. (1). For non-null temperature values, we present and discuss the behavior the total magnetizations and susceptibilities as a function of: the temperature, the crystal field, the exchange coupling interactions and the external magnetic field. The hysteresis loops are illustrated and analyzed when varying the external magnetic field for specific values of the physical parameters: the temperature, the crystal field and the exchange coupling interactions. In order to complete this study, we present the obtained values of the critical exponents corresponding to compound GdN. Such results have been compared with those existing in the literature.

The Half-Metallic Ferromagnetic behavior of some double perovskites attracts much interest. In this work, we studied the magnetic behavior of the double perovskite Pb2FeReO6. The magnetic atoms are Fe and Re and have the spins S=5/2 and {\sigma}=1, respectively. In a first step, we provide a theoretical study of the ground state phase diagrams .In fact, we present and discuss the stable configurations from the all 6x3=18 possible configurations. Secondly, the magnetic properties of this compound when varying different physical parameters is carried out. Besides, we used Monte Carlo simulations (MCS), under the Metropolis algorithm to provide the magnetic behavior of the studied system as a function of the temperature, the crystal field, the exchange coupling interactions and the external magnetic field. In addition, we studied and discussed the critical temperature of the double perovskite Pb2FeReO6. To complete our study, we presented and analyzed the hysteresis loops for specific values of physical parameters.

In this work, a study of the magnetic behavior of the spinel ZnFe2O4 is presented by using the Monte Carlo simulations (MCS). The iron atoms provide the magnetism in this material. In fact, the magnetic spin of moment of the Fe3+ ions is S=5/2. In this context, we propose a Hamiltonian describing and modeling this compound. Firstly, at zero temperature we have studied the ground state phase diagrams of the system in order to find the more stable configurations. On the other hand, for a non-null temperature values, we obtained the results of the Monte Carlo simulations, namely: the magnetizations and the susceptibilities as a function of temperature. The behavior of those physical parameters shows an anti-ferromagnetic behavior with a Neel-temperature of about TN=12 K. This value is found to be in good agreement with the literature. Moreover, the effect of varying the crystal field, the exchange coupling interactions and the external magnetic field is studied and discussed on the behavior of the magnetizations. To complete this study, we presented the magnetic hysteresis loops deducing the antiferromagnetic behavior of the ZnFe2O4 compound.