Search

The kinetics of the semi-infinite Ising model in the presence of a time-dependent oscillating external field is studied within the framework of the mean-field approach. We use the Glauber-type stochastic dynamics to describe the evolution time of this system. We present a variety of phase in a semi-infinite cubic ferromagnet with spin-1 in two different, planes; phase diagrams contain (BF, S 1P, SP) phase, (BF, S 1F, SP) phase, completely ordered phase (BF, S 1F, SF) and completely disordered phase (BP, S 1P, SP), which strongly depend on interaction parameters. The nature first and second orders of the transitions is characterized by studying the thermal behaviors of the dynamic magnetizations. Furthermore, the system exhibits dynamical tricritical phenomenon and the reentrant behaviors. The magnetizations and phase space trajectories are given and discussed. [ABSTRACT FROM AUTHOR]

In this present work, we study the magnetic properties of the polymer nano-systems involving a core-shell structure. In fact, we investigate the effects of the external magnetic field, the anisotropy effect, the exchange coupling interactions and the temperature in order to explicit the magnetic properties of these polymer nano-structure systems. On the other hand, we examine the existence of the compensation temperature induced by the presence of the core-shell structure. Firstly, we present the ground state phase diagrams, in different planes of the physical parameters. On the other hand, we applied the Monte Carlo simulations, at non null temperature values, in order to investigate the thermal behavior of such nano-structure systems. To complete this study, we investigate the anisotropy crystalline effect on the partial and total magnetizations. [ABSTRACT FROM AUTHOR]

In this paper, we study the magnetic properties and the effect of the Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions in a bilayer graphene structure with non-equivalent planes of a ferromagnetic consisting of the spins σ = 1 / 2 and S = 1. The studied system is formed by two magnetic planes (A and B), separated by a number of non-magnetic planes. In fact, the influence of the coupling exchange interactions, the external magnetic field, and the crystal field is investigated and presented as well as the ground-state phase diagrams. Using Monte Carlo simulations, we examine the behavior of the magnetizations and the total magnetization as a function of the values of system parameters. The effect of the RKKY interactions increases for increasing values of the number of non-magnetic planes; for this reason, the studied system becomes disorder when the number of non-magnetic planes increased. When the susceptibility peaks correspond to the reduced critical temperature ( T / J ), this critical temperature is displaced towards the lower temperatures. [ABSTRACT FROM AUTHOR]

In this work, we study the magnetic properties in a nano-hexagonal structure, based on a ferromagnetic Ising model. This system is formed by four hexagonal layers, with the mixed spin σ=1/2 in the inner and spin S=1 in the surface of our system. This latter is modeled by specific Hamiltonian containing different parameters which are the inner and external magnetic fields, the crystal magnetic field, and the exchange coupling interactions. In this study, we generated the ground state phase diagrams and then studied the magnetizations and the wetting phenomena at finite temperature. For this purpose, we used the Monte Carlo method. Moreover, we analyzed the wetting phenomena and the layering transitions appearing under the effect of different parameters of our Hamiltonian. [ABSTRACT FROM AUTHOR]

In this work, we present the calculations for the structural, electronic and optical properties of simple perovskites CaZrO 3-x S x (x = 0, 1, 2 and 3) using density functional theory (DFT) with GGA-PBE as implemented in ABINIT package. The crystal structure of CaZrO 3-x S x (x = 0,1,2 and 3) compound changes with the change of x value. The calculated electronic properties revealed the indirect semiconducting behavior of CaZrO 3-x S x (x = 0, 1, 2 and 3) perovskites. However, the indirect band gap value Eg (R -Γ) drops from 3.36 to 0.48 eV when the parameter "x" increases from 0 to 3. In any case, the optical parameters such as dielectric constant ε (ω), reflectivity R(ω), refractive index n(ω), absorption coefficient α(ω), extinction coefficient k(ω), energy-loss function L(ω), and optical conductivity σ(ω), are also investigated. As results, it can be deduced that CaZrO2S and CaZrOS2 materials have the promising optoelectronic devices in photovoltaic applications. • We studied the perovskites CaZrO 3-x S x (x = 0, 1, 2 and 3) using DFT method. • We applied the GGA approximation. • The electronic and Optical properties have been deduced. • The Band gap values have been obtained and discussed. • The Optoelectronic properties have been discussed. [ABSTRACT FROM AUTHOR]

The magnetic properties of a mixed Rubrene-like nano-island have been extensively investigated using Monte Carlo simulations (MCs) using the Metropolis algorithm in the context of the Blume Capel model. The ground state phase diagrams have been established to display the more stable spin configurations. The effects of various physical parameters on compensation and transition temperatures have been studied. Additionally, triple loops have been found by exploring the hysteresis cycles, which is useful in many applications in multistate memory systems. • We study the magnetic properties of the Rubrene-like nano-island. • The ground state phase diagrams are presented and discussed. • The magnetic properties of the Rubrene-like nano-island structure using Monte Carlo simulations are investigated. • The hysteresis cycle of the Rubrene-like nano-island structure is analyzed. [ABSTRACT FROM AUTHOR]

The magnetic properties of a spin S = 2 Ising system with bilinear exchange interaction J 1 , the biquadratic exchange interaction K , four-spin exchange interactions J 4 and crystal field Δ are discussed using the Monte Carlo simulation. The lattice is divided into two sublattices: A and B, for which we compute the magnetizations m A and m B . The phase obtained diagrams of this system are deduced in the planes: (T, Δ/J 1 ), (K/J 1 , Δ/J 1 ), (Δ/J 1 , J 4 /J 1 ) and (J 4 /J 1 , K/J 1 ). In addition to the usual phases, we found a new phase called nonmagnetic quadratic, for which the magnetizations are m A ≠ m B and the quadrupolar moments are so that are q A = q B . Furthermore, the behavior of the magnetizations as a function of temperature, crystal field, four-spin exchange interactions and biquadratic exchange interaction are deduced. [ABSTRACT FROM AUTHOR]

The aim of this work is to study the magnetic properties of a nano-structure consisting of an anti-ferri-magnetic surface based on a square core-shell. The geometry of the studied system is formed with alternate layers consisting of spins σ = 3/2 in the core and spins S = 1 in the shell. Exactly, we study the effect of the coupling exchange interactions and the crystal field. We use Monte Carlo simulations to investigate the behavior of this nano-structure. Different phase diagrams were found depending on the parameters of the studied system. The influence of the temperature on the critical and compensation behaviors of this system is also examined. Finally, we showed that the compensation temperature can appear for specific values of system parameters. [ABSTRACT FROM AUTHOR]

Using the spin polarized density functional theory (DFT) and exploring the Plane-Wave Self-Consistent Field (PWscf) code implemented in Quantum-ESPRESSO package, we investigate the effect of the Oxygen vacancies (V O ) and the Oxygen interstitial (O i ) on the double perovskite BaSrNiWO 6 . This deals with the magnetic ordering and the electronic structure in such a pure sample exhibiting the insulating anti-ferromagnetic (AFM) state. This study shows that the presence of oxygen deficient defects converts the insulating to half metal with ferromagnetic or anti-ferromagnetic states. The magnetic ordering in BaSrNiWO 6−δ depends on the position of the Oxygen vacancy in the unit cell. However, it has been shown that the Oxygen interstitial preserves the anti-ferromagnetic propriety. We have computed the formation energies of different positions of the Oxygen vacancy (V O ) and the Oxygen interstitial (O i ) in the BaSrNiWO 6 compound. We showed that the formation of V O is easier and vice versa for the O i formation. The obtained results reveal(V O ) and the Oxygen interstitial (O i ) that the anti-ferromagnetic can be converted to ferromagnetic in the double perovskite BaSrNiWO 6 induced by Oxygen vacancies V O . [ABSTRACT FROM AUTHOR]

We perform the ab initio method, the Monte Carlo simulation (MCS) and the mean field approximation (MFA) to examine the magnetic proprieties of the double-perovskite BaCoUO. The first method has been employed for investigating and analyzing the electronic density of state (DOS) in the framework of the generalized gradient approximation (GGA) using the fullpotential linearized augmented plane wave (FP-LAPW) method as implemented in the WIEN2k package. On the other hand, the mean field approximation and the Monte Carlo simulation within the Ising model are applied for studying and discussing the magnetic behavior of the compound under study. To complete our investigation of the system, the magnetizations, the specific heat, the magnetic susceptibilities and the hysteresis cycle of the system have been examined. The results reached through these methods are in agreement with experimental data. [ABSTRACT FROM AUTHOR]

The Monte Carlo simulations have been used to study the magnetic properties and the hysteresis of a nano-shell structure composed of four bands, comprising a ferromagnetic spins σ =±1/2 Ising model. The influence of the surface and inner magnetic fields is responsible for the wetting phenomena and the layering transitions. The behavior of the magnetizations as well as the ground state phase diagrams is presented. We also explore the effect of the external magnetic field, the temperature and the exchange coupling interactions on the hysteresis cycle. [ABSTRACT FROM AUTHOR]

The structural and optoelectronic properties of Cs-based fluoroperovskites CsMF 3 (M = Ge, Sn or Pb) were studied using the generalized gradient approximation of Perdew-burke-Ernzerhof (GGA-PBE) based on density functional theory (DFT) under the ABINIT code. The obtained lattice parameters are found to be in a good agreement with previous theoretical and experimental works. The studied electronic band structures reveal that the studied compounds exhibit a semiconducting nature with a direct band gap at R-point symmetries. The calculated optical properties confirm that CsGeF 3 and CsSnF 3 can be candidates as absorber in solar cell applications. However, the case of perovskite CsPbF3 shows that this material is a promising candidate to absorb ultraviolet radiation. On the other hand, the thermoelectric transport properties such as Seebeck coefficient ( S ), the thermal conductivity (k τ), electrical conductivity (σ τ), power factor ( PF ) and figure of merit ( ZT ) have been studied as a function of temperature (T) and as a function of chemical potential (μ) by using BoltzTraP code to resolve the Boltzmann transport equation. [ABSTRACT FROM AUTHOR]

Structural, electronic and optical properties of Hg 1-x Mg x Se (x = 0, 0.25, 0.5, 0.75 and 1) alloys have been investigated by using density functional theory calculations (DFT) with the generalized gradient approximation under the Perdew–Burke–Ernzerhof (GGA-PBE) method. In fact, we have studied and discussed the structural, electronic and optical properties of the HgSe when substituting the Mercury Hg by Magnesium element (Mg). The calculated structural parameters show a decrease trend with increasing the concentration of doping by the Mg element. The obtained results for the electronic properties indicate that HgSe is a semimetal material. However, Hg 1-x Mg x Se (x = 0.25, 0.5, 0.75 and 1) are semiconductors. Also, such materials exhibit a direct bandgap at Γ point symmetries. The optical parameters such as real and imaginary parts of dielectric function ε (ω) , the refractive index n (ω) , the absorption coefficient α (ω) , the reflectivity R (ω) , the optical conductivity σ (ω) and the energy loss function L(ω) were also studied and discussed. [ABSTRACT FROM AUTHOR]

The magnetic behaviors of a mixed spins (2-1) hexagonal Ising nanowire with core–shell structure are investigated by using the Monte Carlo simulations. The thermal magnetizations, the magnetic susceptibilities and the transition temperatures of core–shell are studied for different values of crystal field and exchange interactions. The thermal and magnetic hysteresis cycles are given for different values of the crystal field. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the Blume-Capel thin film model for mixed spins σ = 3/2 and S = 2 placed on a square lattice with four-spin interactions. In fact, we study the effect of the coupling exchange interactions in the presence of both an external and a crystal field. The ground state phase diagrams are studied for this mixed system, and the stable phases have been established. On the other hand, the magnetic properties, at non-null temperatures are investigated using the Monte Carlo simulations. In order to complete this study, we present the thermal behaviors of the hysteresis loops. The dependencies of the coercitif magnetic field on the crystal field, and/or the four-spin interaction couplings, are also discussed. [ABSTRACT FROM AUTHOR]

Using Monte Carlo method, we study the magnetic proprieties of La 2 FeCoO 6 double perovskite. First, we elaborate the ground state phase diagrams in different planes: ( R 1 , R 2 ), ( R 1 , d ), ( R 2 , d ), ( R 1 , h ), ( R 2 , h ) and ( h , d ), where, the reduced parameters R 1 = J Fe – Fe / J Fe – Co , R 2 = J Co – Co / J Fe – Co , d = Δ / J Fe – Co and h = H / J Fe – Co represent the reduced Fe–Fe, Co–Co exchange coupling interactions, the reduced crystal field and the reduced external magnetic field, respectively. We show that the only stable configurations in these planes are: (±2, ±1/2), (±1, ±1/2) and (0, ±1/2). Then, we investigate the thermal behavior of the magnetizations and the susceptibilities of such a system for the ferromagnetic case. Moreover, we reveal that the increasing exchange Fe–Fe coupling effect increases the critical temperature. We also discuss the hysteresis cycle loops. [ABSTRACT FROM AUTHOR]

Borrowing ideas from Lie algebras, we propose a new nanotube model based on a double hexagonal geometry appearing in the G Lie symmetry. This structure involves two hexagons of unequal side length at angle 30 producing $(\sqrt {3}~\times ~\sqrt {3})R30~^{\circ }$ and (1 × 1) geometries. In this configuration system, the principal unit cell contains 12 sites instead of only 6 ones, arising in the single hexagonal structure on which the graphene-like models are based. More precisely, we engineer a superlattice model based on periodic bilayers consisting of particles with the spins $\sigma =\pm \frac {1}{2}$ having two possible states, placed at sites of the double hexagonal structure. Then, we investigate the phase diagrams and the magnetic properties using the mean field method. In particular, we find six stable phases required by a global Z symmetry associated with the spin values placed at the site of the G double hexagonal structure. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the Blume–Emery–Griffiths thin film model, for mixed spins σ = 3/2 and S = 2, with a biquadratic exchange interaction. More precisely, we study the effect of the coupling exchange interactions in the presence of both an external magnetic and crystal fields. We first elaborate analytically the ground state phase diagrams. Concretely, the stable phases have been discussed. Then, the magnetic properties, at non vanishing temperature, are illustrated using Monte Carlo calculations. To complete this study, we examine the hysteresis loops behavior of the system. [ABSTRACT FROM AUTHOR]

The kinetics of the semi-infinite Ising model, in the presence of a time-dependent oscillating external field, is studied within the framework of the mean-field approach. We use the Glauber-type stochastic dynamics to describe the time evolution of this system. In addition to the well-known phase transitions (ordinary, extraordinary, and surface phase transitions) in the equilibrium case, a dynamical phase appears in which the bulk orders, whereas the surface is disordered. Consequently, a variety of phase diagrams is obtained. Furthermore, the system exhibits dynamical first-order phase transition. The magnetizations and phase space trajectories are given and discussed. [ABSTRACT FROM AUTHOR]

Abstract: Motivated by spintronic device applications, we engineer a superlattice model based on periodic tri-layers consisting of spins , and residing on the sites of a square lattice, interacting with an external magnetic field. We study its phase diagrams and magnetic properties. We determine the corresponding ground state phase diagrams. Then, we show that this Ising lattice model exhibits a ferromagnetic phase , two ferrimagnetic phases , and an antiferromagnetic phase . It is found that the magnetic behaviors depend on the moduli space controlled by the exchange interaction couplings. More precisely, the hysteresis loops have been established. [Copyright &y& Elsevier]

Self-consistent ab initio calculations, based on the DFT (Density Functional Theory) approach and using the FLAPW (Full potential Linear Augmented Plane Wave) method, are performed to investigate both electronic and magnetic properties of the ErRh layers. Polarized spin and spin-orbit coupling are included in calculations within the framework of the antiferromagnetic state between two sites of Er atoms. Magnetic moments considered to lie along axes are computed. The data obtained from the ab-initio calculations are then used as input for the high-temperature series expansions (HTSEs) calculations to compute other magnetic parameters. The exchange integrals between the magnetic atoms in the same sites are given by using mean field theory. The HTSEs of the magnetic susceptibility of ErRh antiferromagnetic spin-S through two model: Heisenberg and XY for ErRh layers, are studied to sixth order series in β=1/ k T. The critical exponent γ associated with the magnetic susceptibility is deduced for the two models. [ABSTRACT FROM AUTHOR]

Self-consistent ab initio calculations, based on DFT (Density Functional Theory) approach and using the FLAPW (Full potential Linear Augmented Plane Wave) method, are performed to investigate both electronic and magnetic properties of the MnO layers. Polarized spin and spin-orbit coupling are included in calculations within the framework of the antiferromagnetic state between two adjacent Mn layers. Magnetic moment considered to lie along (110) axes are computed . Obtained data from ab initio calculations are used as input for the high temperature series expansions (HTSEs) calculations to compute other magnetic parameters. The exchange integrals between the magnetic atoms Mn-Mn and Mn-O in the same layer and between the adjacent bilayers are given by using the mean field theory. The antiferromagnetic energies of MnO layers are obtained. The High Temperature Series Expansions (HTSEs) of the magnetic susceptibility on MnO antiferromagnetic layers through Heisenberg and XY models is given up to tenth order series in ( x= J/ k T). The reduced Néel temperature x is obtained by HTSEs of the magnetic susceptibility and by using the Padé approximant method. The critical exponent γ associated with the magnetic susceptibility is deduced. [ABSTRACT FROM AUTHOR]

Abstract: Self-consistent ab initio calculations, based on the density functional theory (DFT) approach and using the full potential linear augmented plane wave (FLAPW) method, are performed to investigate both electronic and magnetic properties of the MnAu layers. Polarized spin and spin–orbit coupling are included in calculations within the framework of the antiferromagnetic state between two adjacent Mn layers. Magnetic moment considered to lie along a axes are computed. The data obtained from the ab initio calculations are then used as input for the high temperature series expansions (HTSEs) calculation to compute other magnetic parameters. The exchange integrals between the magnetic atoms in the same layer and between the magnetic atoms in the bilayers adjacent are given by using mean field theory. The HTSEs of the magnetic susceptibility of MnAu antiferromagnetic spin-S through two model: Ising and XY layers consisting of l=2, 3, 4, 5, 6 and bulk (∞) interacting layers, are studied to sixth order series in β=1/k B T obtained for free-surface boundary conditions. The effects of finite size on critical-point behavior are studied by extrapolation of the high-temperature series. The Néel temperature T N(l) as a function of the number of l spin layers is obtained by HTSEs of the magnetic susceptibility series by using the Padé approximant method and by MFT theory. The critical exponent γ associated with the magnetic susceptibility is deduced. T N(l) for the l-layers are estimated from the divergence of the staggered susceptibility with an exponent for Ising model of γ(1)=2.96, and for XY model of γ(2)=2.82, which is consistent with the basic assumptions of scaling laws. Our estimates for the shift exponent of the Néel temperature for the two models are obtained. [Copyright &y& Elsevier]

The study of structural, electronic and magnetic alloy properties of the full-Heusler Co 2 FeGe has been undertaken using the first principle method based on the density functional theory (DFT). In this work, we have predicted and underlined the mechanism of the half-metallic behavior of the full-Heusler Co 2 FeGe alloys by using the Monte Carlo simulations. We have used the full potential linear augmented plane wave (FPLAPW) method as implemented in the Wien2K code to forecast the electronic and magnetic properties of the studied system. We have used the generalized gradient approximation GGA for the treatment of exchange energy and correlation. We have also taken into account the strong correlations orbital of Co and Fe atoms by applying the GGA ​+ ​U approximation founded on DFT ​+ ​U. The GGA ​+ ​U gives a good result showing that compound Co 2 FeGe is a half-metallic ferromagnetic (HMF) through a large gap of 1.20 ​eV. The value of the magnetic moment is used as input to calculate the magnetic parameter of this alloy when using the Monte Carlo simulations. By the help of the proposed model the temperature dependency of the magnetization, the susceptibility and the specific heat, is studied. The phase transition is of second order type at the critical temperature point. This temperature is in good agreement with the available experimental data. [Display omitted] • The physical properties of the Heusler compound Co 2 FeGe are studied. • The Monte Carlo study is applied. • The First principle calculations are also applied to this system. • The Curie temperature is determined and discussed. [ABSTRACT FROM AUTHOR]

• The Opto-electronic properties of doped Zirconium dioxide ZrO2 have been studied. • The DFT study is applied under the Quantum Espresso package. • The band gap values have deduced and compared to experimental values. • The doping effect by sulfur is studied and discussed. In this paper, we use density functional theory (DFT) calculations under Quantum Espresso package to characterize the doping effect of sulfur substitution on Zirconium dioxide ZrO2. Through the density of states (DOS) and the band structure (BS) calculations, a direct band gap is found for the pure and doped studied ZrO2 system. The optoelectronic properties analysis shows that the doping with sulfur could considerably decrease the band gap of doped ZrO2 by the presence of an impurity state of sulfur 3p on the up spin of the valence band. The results of the ab-initio density functional theory investigations show that the substitution by sulfur dopants incorporated into the Zirconium dioxide ZrO2 drastically and affect the electronic structure of the studied material. Thus, the doped ZrO2 with sulfur impurities can improve interesting properties in photovoltaic applications. In fact, the doping of Zirconium dioxide ZrO2 with appropriate concentration values of sulfur leads to band gap values in the interval (1–2) eV. [ABSTRACT FROM AUTHOR]

In this manuscript, we investigate the structural, electronic and magnetic properties of the quaternary Heusler alloys ZnCdXMn (X = Pd, Ni or Pt) by using the first-principle calculations. In fact, we explore the competing structure on the magnetic and electronic properties of the Zn-based equiatomic quaternary Heusler alloys ZnCdXMn (X = Pd, Ni or Pt) using the Ab-initio method. On the other hand, we have executed this method in order to determine not only the structural properties, but also the magnetic and the electronic properties of these alloys. The motivation of this work is to improve the competition between the austenitic and martensitic phases on the magnetic and electronic properties of the equiatomic quaternary Heusler Alloys ZnCdXMn (X = Pd, Ni or Pt), and their half-metallic behavior for the austenitic structure and 100% SP polarization. These alloys are useful in the spintronic devices uses. • The Quaternary Heusler ZnCdXMn (X = Pd, Ni and Pt) alloys have studied. • The Half-metallic behavior of this alloy has improved for the cubic structure. • The Density of states and Band structure have been illustrated by Ab-initio calculations. • The Spin Polarizations of these alloys are calculated for the both cubic and tetragonal structures. [ABSTRACT FROM AUTHOR]

In this paper we study the structural, the electronics and the magnetic properties of the perovskite YMnO 3. The ab-initio calculations of this compound were performed using the full potential linearized augmented plane wave form with total potential (FP-LAPW) method in the context of the density functional theory (DFT) implemented in the Wien2K code. The potential for exchange and correlation has been addressed by the GGA approximation. The electronic properties show that the YMnO 3 perovskite material exhibits a metallic behavior when using the GGA approximation. The Monte Carlo simulations study showed that the YMnO 3 material undergoes a ferromagnetic to paramagnetic phase transition at critical temperature Tc = 145 K. • The Perovskite YMnO 3 is studied in this work. • The Monte Carlo simulations are applied and discussed. • The DFT Method is applied to understand its properties. • The Magnetic Properties are investigated. • The Metallic behavior and Critical temperature are deduced. [ABSTRACT FROM AUTHOR]

In this paper, we inspect the magnetic properties of a core/shell Kekulene-like structure consisting of mixed spins (σ = 2; S = 1), by means of Monte Carlo simulations. Firstly, we carry out an analysis of the ground state phase diagrams to determine all probable and stable configurations depending on the minimization of the energies of the system. Furthermore, the magnetizations and susceptibilities as a function of temperature are obtained with the effect of the crystal field and the exchange coupling interactions of the system. To conclude, we discuss the hysteresis loops as a function of the external magnetic field. • The magnetic properties of the Kekulene-like structure are studied. • The ground state phase diagrams of the Kekulene-like structure are examined. • Monte Carlo Simulations are performed. • The susceptibility and the hysteresis loops are studied and discussed. [ABSTRACT FROM AUTHOR]

In this work, we are studying structural and electronic properties of the solar perovskites photovoltaic CsXCl3 (X = Sn, Pb or Ge) using the ab-initio calculations under the Quantum Espresso package. The total and partial density of states (DOSs) have been elaborated and discussed for each material: CsSnCl3, CsPbCl3 and CsGeCl3. On the other hand, the band structure of each one of these materials has been established. It is found that these materials exhibit a non-magnetic and semi-conductor behavior. The dependency of the band gap of the solar perovskites photovoltaic CsXCl3 (X = Sn, Pb or Ge) is illustrated as a function of the lattice parameter 'a' (Å). It is found that when increasing the lattice parameter the band gap increases for all the materials: CsSnCl3, CsPbCl3 and CsGeCl3. In addition, for a fixed value of the lattice parameter 'a' the band gap increases when we move from one material to another: CsSnCl3, CsGeCl3 and CsPbCl3, respectively. To complete this study, we have inspected the effect of the spin orbit coupling (SOC) correction on the band gap energy of the different solar perovskite materials CsXCl3 (X = Sn, Pb or Ge), when using the optimized lattice parameter values. Our results revealed that the (SOC) effect is to decrease the band gap energy values of the three studied solar perovskite materials. [ABSTRACT FROM AUTHOR]

In this work, we study the magnetic properties of a nanotube core-shell like-structure using Monte Carlo simulations. The system consists of an anti-ferrimagnetic hexagonal core-shell nanotube like-structure with mixed spins σ = 1 in the core and S = 3/2 in the shell. We start by discussing the ground state phase diagrams corresponding to several physical parameters. Then the magnetizations and the susceptibilities have been analyzed. Besides, we explore the thermal magnetization behavior under the effect of the exchange coupling interactions. Furthermore, we investigate the existence of the compensation temperature resulting from the variation of the coupling coefficients. Finally, the variation of the total magnetization and total susceptibility as a function of the exchange coupling interactions and the crystal field has been discussed. • Compensation Behavior of an Anti-ferrimagnetic Core-Shell Nanotube Like-Structure. • Monte Carlo Study has been discussed. • The Monte Carlo simulations technique used to simulate. • The behavior of the Compensation temperature has been established. • A Core-shell nanotube structure has been considered. [ABSTRACT FROM AUTHOR]

• We study the dielectric properties of a monolayer coronene like nano-structure. • The blocking temperature for different physical parameters is investigated. • The ground state phase diagrams are presented and discussed. • The dielectric properties of a monolayer coronene like nano-structure using Monte Carlo simulations are investigated. • The hysteresis cycles of a monolayer coronene like nano-structure are analyzed. In this paper, we study the dielectric properties of a monolayer coronene like nano-structure with mixed spins (S = ± 2 , σ = ± 5 / 2), using Monte Carlo simulations. The ground state phase diagrams in different planes are studied. In addition, we examine the blocking temperature for different exchange coupling interactions. Moreover, we explore the effects of the crystal field on the total polarizations. Finally, the electric hysteresis cycles are given for different values of temperatures and exchange coupling interactions. [ABSTRACT FROM AUTHOR]

• The equiatomic quaternary Heusler alloy CoFeTiSn has been studied. • The half-metallic behavior of this alloy has been studied and improved. • The electronic properties have been investigated by the ab-initio method. • The critical temperature is presented and discussed by Monte Carlo simulations. In this article, we study the exchange coupling interactions of the equiatomic quaternary Heusler alloy CoFeTiSn, using the two methods: Monte Carlo simulations and the ab-initio method. In a first step, we use the ab-initio calculations to investigate the structural, the electronic and the magnetic properties of this alloy under the GGA method. The analysis of the energy dependence on the lattice parameter a (Å) of the equiatomic quaternary Heusler alloy CoFeTiSn, is discussed for different atomic configurations. The ferromagnetic configuration is found to be the more stable one, with an optimal lattice parameter value 6.00 Å. On the other hand, the electronic structure results show that the compound CoFeTiSn exhibits a half-metallic character and a spin polarization of 100% at the Fermi-level. The total magnetic moment of this alloy is found to be equal to 2.00 μ B which follows the Slater Pauling rule. Our results support the half-metallic behavior of the studied material. In order to complete this study, we reported the dependence of the critical transition temperature as a function of the parameter α of the equiatomic quaternary Heusler alloy CoFeTiSn. We showed that the critical temperature increases almost linearly with an increase of the values of the parameter α. [ABSTRACT FROM AUTHOR]

In this paper, we study the magnetic properties of a diluted core-shell borophene structure. The system is composed by the mixed spins σ = ±1, 0 (in the core) and S = ±3/2, ±1/2 (in the shell). Indeed, the originality of this work is to introduce the non-magnetic atoms in the shell part of the borophene monolayer system and study their effects on the magnetic properties behavior. Firstly, the ground state phase diagrams for different parameters are reported and discussed. Numerically, we use the Monte Carlo simulations (MCS) to study the effect of the dilution concentration on the magnetizations and susceptibilities of the system. Moreover, the compensation and transition temperatures decrease when increasing the dilution concentration parameter. Furthermore, the effect of the dilution concentration on the total magnetization versus the crystal field is discussed. Finally, the effects of the dilution concentration and the temperature on the hysteresis cycles are investigated. • The magnetic properties of a diluted core-shell borophene structure using Monte Carlo simulations are studied. • The ground state phase diagrams are presented and discussed. • The existence of the compensation and transition temperatures for special physical parameters. • The hysteresis cycles of a core-shell Borophene structure are analyzed. [ABSTRACT FROM AUTHOR]

In this manuscript, we investigate the electronic and magnetic properties of the YFeCrZ (Z = Al, Sb and Sn) quaternary Heusler alloys were investigated by using first-principles calculations and Mont Carlo simulations. The results of the electronic structures show that the YFeCrZ (Z = Al, Sb and Sn) alloys exhibit a half-metallic character. This half-metallic behavior is confirmed by the integral value of the total magnetic moment, which is 2.00 μ B , for the YFeCrAl compound. This is found to follow the Slater Pauling rule. At null temperature (T = 0 K), we performed and illustrated the ground state phase diagrams in different planes of the physical parameters. In fact, we have studied and illustrated the magnetic behavior of the studied system as a function of temperature and the reduced crystal field. Finally, we have presented and discussed the hysteresis cycles as a function external magnetic field. • The Quaternary Heusler YFeCrZ (Z = Al, Sb and Sn) alloys are studied via Ab-initio and Monte Carlo methods. • The Half-metallic behavior of the Quaternary Heusler YFeCrZ (Z = Al, Sb and Sn) has been improved. • The Slater Pauling rule is confirmed by the integral value of the total magnetic moment. • The Ground state study and Monte Carlo simulations are presented and discussed for the Quaternary Heusler alloys. [ABSTRACT FROM AUTHOR]

• We study the magnetic properties of the Heusler compound NiMnCuSb. • We perform DFT and Monte Carlo simulations. • The physical parameters effect is studied and discussed. • The hysteresis loops are presented and discussed. In this paper, Monte Carlo simulations (MCS) under the Metropolis algorithm and the Ab-initio calculations based on the Quantum espresso code, are used to simulate the structural, the magnetic properties and the diagram phases of the quaternary Heusler compound MnNiCuSb. As far as we know, this alloy has not been neither synthesized nor theoretically studied. We have applied the Ab-initio calculations to investigate the density of states (DOS) of this compound. Such method showed that this material MnNiCuSb, has three magnetic elements: Mn, Ni and Cu. In a first step, we have presented and discussed the ground state phase diagrams in different planes corresponding to different physical parameters. In order to apply the Monte Carlo Simulations, we modeled the three magnetic elements (Mn, Ni and Cu) by the magnetic spin moments: S = 2, σ = 1 and Q = 1/2, respectively. Our calculations showed that for null temperature values, this compound presents interesting properties, when exploring the behavior of the total magnetizations as a function of temperature and external magnetic field. Also, we have studied the effect of varying the crystal magnetic field on the coercive field for fixed temperature and exchange coupling interactions. [ABSTRACT FROM AUTHOR]

In this paper, the magnetic properties of a bi-layer graphyne structure have been studied using Monte Carlo simulations. The considered system is composed of two planes of graphyne with mixed spins: σ = 7/2 and S = 1. Firstly, the ground state phase diagrams for zero temperature are reported and discussed. Secondly, the magnetic properties for the studied system are examined for non-zero temperature. The effects of exchange coupling interaction and temperature on magnetization, susceptibility and transitional temperature. Furthermore, the effects of the crystal field on total magnetization of the system have been exhibited. Finally, the effect of the ferrimagnetic parameter, temperature and crystal field on the hysteresis cycles have been determined. The obtained results have been compared with theoretical and experimental researches. • We study the magnetic properties of a bi-layer graphyne structure. • The ground state phase diagrams are presented and discussed. • The magnetic properties of a bi-layer graphyne structure using Monte Carlo simulations are investigated. • The hysteresis cycles of a bi-layer graphyne structure are analyzed. [ABSTRACT FROM AUTHOR]

• We study the magnetic properties of bi-layer graphyne separated by non-magnetic layers with RKKY interaction. • The ground state phase diagrams are presented and discussed. • The magnetic properties of a bi-layer graphyne system using Monte Carlo simulations are investigated. • The hysteresis cycles of a bi-layer graphyne structure are analyzed. In this paper, we study the magnetic properties of a bi-layer graphyne structure with RKKY (Ruderman-Kittel-Kasuya-Yoshida) interaction. The system is composed by two magnetic layers with mixed spins σ = 3/2 and S = 1, separated by (L) non-magnetic ones. Firstly, the ground state phase diagrams are reported and discussed. Then we use the Monte Carlo simulations in order to determine the effect of the RKKY interaction on the system magnetic properties. We find that the transition temperature increases when decreasing the number of non-magnetic layers. This result is confirmed by the displacement of the peak of susceptibility towards the high temperatures. Furthermore, the variation of the total magnetization versus the crystal field remains independent of the parameter L when this one is greater than or equal to three. Besides, the hysteresis loop stays invariable for L ≥ 2. [ABSTRACT FROM AUTHOR]

In this paper, the dielectric properties of a monolayer nano-graphyne structure, with mixed spins σ = 7/2 and S = 1, have been studied, using Monte Carlo simulations. Firstly, the ground state phase diagrams for a zero temperature value are reported and discussed. Secondly, the dielectric properties of the studied system for a non-zero temperature are examined. The effects of the temperature, the external longitudinal electric and crystal fields on polarization, dielectric susceptibility and hysteresis cycles have been investigated. • The thermodynamic and dielectric properties of a monolayer nano-graphyne structure using Monte Carlo simulations are investigated. • The ground state phase diagrams are presented and discussed. • Blocking temperature has been deduced for different physical parameters. • The hysteresis cycles of a monolayer nano-graphyne structure are analyzed. [ABSTRACT FROM AUTHOR]

The magnetic properties of a mixed spins (7/2, 1) anti-ferrimagnetic ovalene nano-structure have been investigated using Monte Carlo simulations. We start by discussing the ground state phase diagrams corresponding to several physical parameters. Then the effects of the crystal field, the exchange coupling interactions and the external magnetic field on the magnetizations, the compensation temperatures and the hysteresis behaviors have been studied. Interesting results have been found, especially, the appearance of two compensation temperatures and their behaviors according to different physical parameters. • Magnetic properties of ovalene nano-structure are studied using Monte Carlo simulations. • Ground state phase diagrams of ovalene nano-structure have established given. • Existence of two compensation temperatures for a special physical parameters. • Two super-paramagnetic phases are observed. • Hysteresis cycles of ovalene nano-structure have been investigated. [ABSTRACT FROM AUTHOR]

This work deals with the magnetic behavior of the yttrium manganite oxide YMnO3 which can crystallize in either the hexagonal (h-YMO) or orthorhombic (o-YMO) structure. These two structures are investigated using Monte Carlo simulations under the Metropolis algorithm. In a first step, we have elaborated and discussed the ground-state phase diagrams in different planes corresponding to different physical parameters. The study of the ground-state phase diagrams is done in the absence of any temperature fluctuations. Then we examine the critical behavior and the dependency of the magnetizations and the susceptibilities as a function of the temperature, the crystal field, the exchange coupling interactions and the external magnetic field. On the other hand, we have illustrated the behavior of the magnetizations as a function of the exchange coupling interactions to show and underline the magnetic atoms Mn–Mn for fixed values of the other physical parameters. In addition, we have investigated and discussed the effect of varying the exchange coupling interactions on the total magnetizations, for fixed temperature values. To complete this study, we have provided and analyzed the hysteresis cycles of the studied manganite oxide perovskite YMnO3 compound as a function of the external magnetic field, for specific values of the crystal field, the exchange coupling interactions and the temperature. [ABSTRACT FROM AUTHOR]

A new theoretical study of the magnetic triple perovskite LaSr2Cr3O9 is presented in this work. The all possible configurations have been studied and discussed in the absence of any temperature (T = 0 K). For a finite temperature value, we use Monte Carlo simulations to underline the critical behavior of this system. The transition temperature is found to be around 100 K. The dependency of the total magnetizations is a function of the reduced crystal field and the reduced external magnetic field. In addition, the hysteresis loops have been carried out for different temperature values. Finally, the reduced remanent magnetizations have been presented as a function of temperature. [ABSTRACT FROM AUTHOR]

Context: Nowadays, Perovskite materials with diverse compositions and structures have garnered significant attention for their potential applications across various industrial and technological fields. Here, we investigated the structural, electronic, optical, thermodynamic, thermoelectric, and magnetic properties of perovskite PrFeO 3 using density functional theory and Monte Carlo simulations. The optimization results demonstrate that the ferromagnetic phase is more stable than the antiferromagnetic phase. Under the GGA + SOC + U and GGA + mBJ approaches, the electronic results of the PrFeO 3 compound expose the half-metallic and magnetic behavior. It was also demonstrated that introducing dilatation strain can effectively enhance both the mechanical and thermal stability of PrFeO 3 . Additionally, the optical properties show that this material has potential uses for solar cells because of its capacity to absorb light in the ultraviolet (UV) spectrum. The maximum values of the Seebeck coefficient reach 90 µV/K at 1000 K, indicating the potential of PrFeO 3 as an efficient thermoelectric material. The magnetic properties exhibit a first transition of spin reorientation (T SR ) at 171.44 K, followed by a second-order transition at 707.15 K. This investigation provides valuable insights into the unstudied aspect of Perovskite PrFeO₃., Methods: To carry out this investigation, we employed the density functional theory (DFT) implemented in the Wien2k package. To determine the exchange-correlation potential, we utilized the GGA-PBE (Perdew, Burke, and Ernzerhof) approach. The SOC was included based on the second-variational method using scalar relativistic wavefunctions, and electron-electron Coulomb interactions for Fe and Pr are considered in the rotationally invariant way GGA + SOC + U. In this paper, the effective parameter U eff  = U - J was adopted, where U and J stand for the Coulomb and exchange parameters, respectively. Also, we opted for the modified Becke-Johnson potential (mBJ) for comparison. The thermodynamic properties are obtained using the quasi-harmonic Debye model via Gibbs2 software programs. For the calculation of thermoelectric coefficients, a combination of first-principles band structure calculations and the Boltzmann transport theory within the rigid band approximation (RBA) and the constant scattering time approximation (CSTA) was employed, utilizing the BoltzTrap code. Subsequently, we delve into the magneto-caloric and magnetic properties by employing Monte Carlo simulations., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Context: As new materials, the ternary chalcogenides have recently brought scientists' attention. These materials are a novel class of semiconducting chemical compounds. They allow the increase of the photo-conversion efficiency, the performance, and the cheap energy cost. Such materials also provide a wide range of physical and chemical applications., Methods: The used investigation employs Density Functional Theory (DFT) implemented in the Wien2k package to systematically characterize the physical properties of ternary chalcogenide compounds XBiSe 2 (X = Li, Na and K). Such method emphasizes their applicability to energy conversion technologies. Scrutinizing their electronic, optical, and thermoelectric properties elucidates the effect of alkali metal substitution on performance metrics. The results not only advance knowledge of these materials' physicochemical behaviors but also reveal their potential for tailored functionalization in next-generation energy and optoelectronic systems, marking a significant stride in material science and application-oriented research., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)