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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]

The ability to tune and control the magnetic phases of two-dimensional (2D) nanomagnets at room temperature is indispensable for the development of future spintronics and low-dimensional spin circuits. In this work, a first-principles-based investigation combined with a Monte Carlo simulation based on a 2D Ising model is used to investigate the electronic and magnetic behaviour of a recently discovered 2D material, Cr2Ge2Se6 over a large range of strain and electric field strength. This material offers ferromagnetic antiferromagnetic and semiconductor metallic phase transitions in different regimes. In the presence of strain, a colossal enhancement of the critical temperature (Tc) is observed, from 149 K to 885 K. The application of an electric field allows a further enhancement of the Tc to a value of 919 K, offering a supreme enhancement (~517%), compared to its natural condition. The origin of this behavior can be traced to a super-exchange interaction between the Cr and Se atoms and the intrinsic magnetic anisotropy of Cr2Ge2Se6. The presence of external stimuli engenders spontaneous symmetry breaking with an enhanced magnetic moment (~4.36 /Cr atom), a significant intrinsic spin polarisation (~100%) in a half-metallic regime, and a very high critical temperature. The insights of the current investigation could be useful for future developments in multi-stimuli-assisted room-temperature ferromagnetism and electronic phase control, which are of great significance for future magneto-electronic applications. [ABSTRACT FROM AUTHOR]

The antiperovskite Co4N is studied using density functional theory (DFT) calculations and Monte Carlo (MC) simulation within the framework of the Ising model. The structural, density of states (DOS), and band structure calculations show that Co4N is a ferromagnetic material having a higher magnetic moment, a large spin polarization ratio, and exhibits a metallic behavior. The investigated elastic constants, phonon dispersion, and phonon DOS show that the Co4N compound is mechanically and dynamically stable. It is also found that the Co4N is ductile from the Poisson's ratio, Pugh's ratio, and Cauchy pressure. The thermodynamic parameters like heat capacity, Debye and melting temperature are calculated. The magnetization, magnetic susceptibility, and the Curie temperature of magnetic transition are estimated using MC simulations based on the Ising model. The obtained value of TC is in good agreement with available theoretical work. [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]

We investigate some critical phenomena of a Ising ferrimagnetic system on a square lattice with spins $Q=\pm 7/2, \pm 5/2, \pm 3/2$ , and ±1/2 in a $B$ sublattice and spins $S=\pm 5/2, \pm 3/2$ , and ±1/2 in a $A$ sublattice in presence of an $h'$ external magnetic field, such that $Q$ and $S$ are the nearest-neighbors ferrimagnetically coupled. Using Monte Carlo simulations, we calculate the finite-temperature phase diagrams of magnetization, specific heat, and magnetic susceptibility of the model. The system is defined by a Hamiltonian $(\mathcal {H})$ that contains ferromagnetic next-nearest-neighbors interactions between $S$ spins ($J'_{2}$), as well as external magnetic field and anisotropy interactions at each point of lattice. For a defined range of parameters in $\mathcal {H}$ , the system exhibits discontinuities in their physical variables and spin compensation behaviors. In the planes $J'_{2}-k_{\mathrm{ B}}T'$ and $h'-k_{\mathrm{ B}}T'$ , we analyze the relationship between the critical, compensation, and discontinuous phase transition temperatures with the external magnetic field and the next-nearest-neighbors interaction between $S$ spins. We found that the existence of discontinuous phase transition depends on the strengths of $h'$ and $J'_{2}$. [ABSTRACT FROM AUTHOR]

The Monte Carlo simulation has been used to investigate the magnetic properties of a mixed spin-1 (sublattice A) and spin-1/2 (sublattice B), where each sublattice has a rectangular structure and the whole lattice system forms a 2-D centered rectangular lattice. Five possible interactions are considered. Namely, two S–S interactions and two $\sigma $ – $\sigma $ interactions depend on crystal direction, and an antiferromagnetic interaction between the two sublattices is taken. Our results show that the critical temperature increases with increasing the variation of any exchange interactions. The existence of the compensation temperature depends on the balance between the S–S interactions along and $\sigma $ – $\sigma $ interactions along [01] directions. [ABSTRACT FROM AUTHOR]

The band alignment, intrinsic ferromagnetism, Dzyaloshinskii-Moriya interaction, magnetic anisotropy and critical temperature (T C) of a GdI 2 /GeC van der Waals (vdW) heterostructure were systematically investigated by first-principles calculations and Monte Carlo simulations. The proposed GdI 2 /GeC vdW heterostructure is a bipolar magnetic semiconductor with Type-I band alignment, large in-plane magnetic anisotropy energy (MAE) of − 0.912 mJ/m2 and high critical temperature of 466 K. In addition, under biaxial strains, the heterostructure transformed from semiconductor into metal, while the easy magnetization axis maintained in-plane and T C increased. The results indicated that the GdI 2 /GeC vdW heterostructure presented large MAE and high T C , having potential applications in spintronic devices. [Display omitted] ● The heterostructures is a bipolar magnetic semiconductor. ● The heterostructures with large in-plane magnetic anisotropy. ● The heterostructures with high critical temperature 466 K. [ABSTRACT FROM AUTHOR]

In this study, a bilayer Kagome lattice with RKKY interaction is described using a ferrimagnetic mixed spin-3/2 and spin-2 Ising model. Interesting compensation temperature and hysteresis loops of the system generated by various physical parameters, such as the crystal fields of sublattices (D a , D b), the interlayer exchange coupling (J R) and the intralayer exchange coupling (J b) are explored using Monte Carlo simulation. The results demonstrate that the compensation temperature (T comp), weaker D a and J b , and stronger D b , are favourable for the emergence of the compensation temperatures. Besides, under certain physical parameters, the system may exhibit triple-loop hysteresis behavior and multiple magnetization plateaus. • A ferrimagnetic mixed-spin (3/2, 2) Ising model on the bilayer Kagome lattice with RKKY interaction was proposed. • The effects of the crystal field, exchange coupling and non-magnetic layer were studied. • Magnetization, partial magnetization, and susceptibility were discussed. • Phase diagrams of the critical and compensation temperatures were obtained. • Interesting multi-loop hysteresis characteristics and magnetization plateaus were found. [ABSTRACT FROM AUTHOR]

We used mean-1eld theory based on the Bogoliubov inequality for the Gibbs free energy to examine the magnetic properties of a mixed spin-5/2 and spin-7/2 Blume-Capel ferrimagnetic system. The thermal behaviours of the system magnetization are classi1ed according to the extended Néel nomenclature. The system exhibits compensation phenomena where a complete cancellation of sublattice magnetizations is observed below the critical temperature. Temperature-dependent phase diagrams are constructed for the case of unequal sublattice crystal 1eld interactions. Under appropriate conditions, our calculations reveal 1rst-order transitions in addition to second-order ones previously observed in Monte Carlo simulations. [ABSTRACT FROM AUTHOR]

The magnetic properties of the mixed spin-1 and spin-5/2 Ising ferrimagnetic model on a hexagonal lattice have been studied using the Monte Carlo simulations. The hexagonal lattice study is formed by alternate layers of spins σ = 1 and S = 5 ∕ 2 . The thermal variations of the magnetizations are given. The magnetic hysteresis cycles are established for different values of exchange interactions, crystal-field and temperatures. The magnetic coercive field is deduced. [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]

We study the thermodynamic and magnetic properties of an Ising bilayer ferrimagnet. The system is composed of two interacting non-equivalent planes in which the intralayer couplings are ferromagnetic while the interlayer interactions are antiferromagnetic. Moreover, one of the planes is randomly diluted. The study is carried out within a Monte Carlo approach employing the multiple histogram reweighting method and finite-size scaling tools. The occurrence of a compensation phenomenon is verified and the compensation temperature, as well as the critical temperature for the model, are obtained as functions of the Hamiltonian parameters. We present a detailed discussion of the regions of the parameter space where the compensation effect is present or absent. Our results are then compared to a mean-field-like approximation applied to the same model by Balcerzak and Szałowski (2014). Although the Monte Carlo and mean-field results agree qualitatively, our quantitative results are significantly different. [ABSTRACT FROM AUTHOR]

In this paper, we study the magnetic properties of ferrimagnetic mixed spins with integer σ = 2 and half-integer S = 7 / 2 in a Blume–Capel model, using Monte Carlo simulations. The considered Hamiltonian includes the first nearest-neighbors and the exchange coupling interactions on the two sub-lattices. The effect of these coupling exchange interactions, in the presence of both the external magnetic field and the crystal field, are studied. The magnetizations and the corresponding susceptibilities are presented and discussed. Finally, we have interpreted the behaviors of the magnetic hysteresis of this model. [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]

• The critical temperature of FeNi and FePt alloys using Heisenberg interaction is closer to the experimental value than the Ising interaction. • The FeNi and FePt alloys prefer a ferromagnetic phase over the ferrimagnatic phase. • The Ising interaction predicts higher critical temperature for the FeNi alloy than the Heisenberg interaction. • The Heisenberg interaction predicts higher critical temperature for the FePt alloy than the Ising interaction. A Monte Carlo simulation has been used to explore the magnetic properties of L1 0 ordered FeNi and FePt binary alloys. Our Hamiltonians include Heisenberg interaction or Ising interaction. Our calculations of variations of specific heat C v , magnetic susceptibility χ and the magnetization M with the temperature T showed that predicted critical temperature for ferromagnetic phase is very close to the experimental values for these alloys. Also, thermal hysteresis loops, magnetic remanence, and the coercive field have been calculated. Moreover, the magnetic properties of the ferrimagnetic phase are presented. [ABSTRACT FROM AUTHOR]

The magnetic properties of ferrimagnetic spin-2 and 3/2 Ising-typed thin films are studied by Monte Carlo simulation. The critical temperature is obtained for different values of thickness of the thin film and for different exchange interactions. The total magnetization has been determined for different values of exchange interactions in surface and in bulk and different temperatures. The magnetic hysteresis cycle is obtained for different values of exchange interactions ferro and antiferromagnetic in the surface and in the bulk and for different values of temperatures for a fixed size of the film thickness. The coercive field increase with increasing the film thickness. [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]

• The mixed spin Ising model is generally used as a modeling tool to study ferrimagnetism. • Monte Carlo simulation to study the critical and the compensation behaviors of a cubic lattice considering a mixed spin- 3/2 and spin-1 Ising ferrimagnetic model. • The presence of crystal and external magnetic fields is not sufficient to generate the compensation phenomenon in a mixed spins. In this study, we perform Monte Carlo simulations to study the magnetic properties of a mixed Ising model on a cubic lattice where spins S i A = 1 and σ J B = 3/2 are located in sublattice A and B, respectively. The proposed Hamiltonian includes coupling to nearest-neighbors interactions, next-nearest-neighbors interactions, crystal fields D S and D σ and external magnetic field h. We perform exact ground-state calculations for our model. The obtained results show the behavior of the critical temperature with the presence of the compensation temperatures under a certain range of parameters. Particularly, we found that the existence of compensation temperatures depends on the strength of the coupling to the next nearest neighbors between the S i A spins and between the σ J B spins, and it appears in a certain range of values of the external magnetic and crystal field of different spins. [ABSTRACT FROM AUTHOR]

We applied Monte Carlo simulation to investigate the thermodynamic properties and hysteresis loops of the hexagonal core-shell nanoparticle described by a ferrimagnetic mixed-spin (3/2, 5/2) Ising model. The results revealed the significance of the single-ion anisotropy, exchange coupling, external magnetic field in dominating various thermodynamic quantities and hysteresis loops. We obtained the variation of the critical temperature with various parameters. Under certain parameter conditions, the system may exhibit rich multiple-loop hysteresis behaviors, depending on the competition among the physical parameters. An Ising model of nanoparticle with hexagonal core-shell structure is proposed. The multiple profiles and saturation values of the magnetization are discovered in the system. [Display omitted] • A ferrimagnetic hexagonal core-shell nanoparticle was proposed under an external magnetic field. • Magnetization, susceptibility, and internal energy were discussed by Monte Carlo simulation. • The compensation temperature was found under the effect of single-ion anisotropy. • Multiple-loop hysteresis behaviors were discovered due to the competition among different physical parameters. [ABSTRACT FROM AUTHOR]

The structural, electronic, and magnetic properties of the Zn x Ni 1-x Fe 2 O 4 compounds are studied using several theoretical methods such as first-principle calculations based on density functional theory (DFT+U), Monte Carlo simulations, High temperature series expansions(HTSE) combined with the Padé approximants(PA) and mean-field theory. The total magnetic moment increases and the Curie temperature decreases with Zn substitution. The gap energy results of 1.3 eV obtained using GGA+U are reasonable compared to the available experimental data. The ZnFe 2 O 4 possesses the insulating ground state and antiferromagnetic ordering. The critical exponent γ associated with the magnetic susceptibility is obtained. The dependence of the magnetization and the magnetic susceptibility on temperature is established for Zn x Ni 1− x Fe 2 O 4 using Monte Carlo study. [ABSTRACT FROM AUTHOR]

• A ferrimagnetic double-layer core–shell Ising graphene nanoisland was studied in an oscillating magnetic field. • The dynamic order parameter, the susceptibility and the internal energy were discussed by Monte Carlo simulation. • The phase diagrams as well as the multiple-loop hysteresis behaviors were exhibited. • The behaviors of the coercivity and remanence under the influence of various parameters were investigated. By using Monte Carlo simulations, we discuss the dynamic magnetic properties of a double-layer core–shell graphene nanoisland with mixed-spin (2, 5/2) configuration in an oscillating magnetic field. We investigate the influence of exchange couplings, oscillating magnetic field, and temperature on the dynamic magnetic and thermodynamic properties of the system. We obtain the various characteristic curves of the dynamic order parameter, susceptibility, and internal energy as well as hysteresis loops. To better understand the impact of these physical parameters on the phase transition of the system, the phase diagrams are depicted. It should be noticed that the system can exhibit multiple-loop hysteresis behaviors under certain conditions. Besides, we plot the coercivity and remanence of the system under the influence of various parameters. [ABSTRACT FROM AUTHOR]

A quantity known as the contact is a fundamental thermodynamic property of quantum many-body systems with short-range interactions. Determination of the temperature dependence of the contact for the unitary Fermi gas of infinite scattering length has been a major challenge, with different calculations yielding qualitatively different results. Here we use finite-temperature auxiliary-field quantum Monte Carlo (AFMC) methods on the lattice within the canonical ensemble to calculate the temperature dependence of the contact for the homogeneous spin-balanced unitary Fermi gas. We extrapolate to the continuum limit for 40, 66, and 114 particles, eliminating systematic errors due to finite-range effects. We observe a dramatic decrease in the contact as the superfluid critical temperature is approached from below, followed by a gradual weak decrease as the temperature increases in the normal phase. Our theoretical results are in excellent agreement with the most recent precision ultracold atomic gas experiments. We also present results for the energy as a function of temperature in the continuum limit. [ABSTRACT FROM AUTHOR]

Monte Carlo simulation has been performed to explore the compensation temperature and the critical behavior on a triple layer spin (1-1/2-1) cubic system with ferrimagnetic coupling at the two interfaces. Our results showed that the compensation temperature T c o m p is less influenced by increasing the number of layers or the exchange coupling of the spin 1 2 layer. Gradual increases in the critical temperature T c is shown with increasing the exchange coupling in spin 1 layers or spin 1 2 layer. Finally, the above results have been confirmed by the simulation performed on the heat capacity and Binder cumulant. • The compensation temperature is less influenced by increasing the number of layers. • Compensation temperature disappears for specific values of exchange interaction. • Gradual increases in the critical temperature with increasing the exchange coupling. • Compensation temperature disappears for specific values of exchange interaction. [ABSTRACT FROM AUTHOR]

In this paper, we have studied the structural, electronic, magnetic, elastic and thermodynamic properties of the cubic perovskite system C r 4 N using the first-principles calculations based on density functional theory (DFT) with the generalized gradient approximation (GGA). Our results show that the C r 4 N is more stable in a ferrimagnetic configuration (FIM) and in a ferromagnetic arrangement (FM), C r 4 N is nonmagnetic compound (NM). Density of States (DOS) and band structure calculations show a metallic behavior of C r 4 N. The calculated elastic constants satisfy the Born mechanical stability criterion. Based on the calculated data of Poisson's ratio, C r 4 N have ionic bonding. According to the B/G values, the compound under investigation is found to be brittle nature in FIM configuration and ductile nature in FM and NM configurations. The exchange interactions of C r 4 N , were calculated to obtain the critical temperature (T C) from Monte Carlo calculations. The obtained value of T C (295 K) is in good agreement with other theoretical works. • C r 4 N has a metallic behavior. • The calculated specific heat C v of C r 4 N exhibits Dulong–Petit at high temperature. • The Poisson's ratio shows that C r 4 N have ionic bonding. [ABSTRACT FROM AUTHOR]

• Critical properties of Fe-Al alloys in the bcc phase – phase diagram. • Ising model with exchange and superexchange interactions. • Monte Carlo simulations taking the effects of the Al cluster sizes. A spin-1/2 Ising model, defined in the body centered cubic lattice, is used to describe some of the thermodynamic properties of Fe p - Al q alloys, with p + q = 1. The model assumes, besides the nearest-neighbor exchange coupling, the existence of further next-nearest-neighbor superexchange interactions, where the latter ones depend on the aluminum atoms cluster size. The Ising system so considered is studied by employing Monte Carlo simulations, using a hybrid algorithm consisting of one single-spin Metropolis move together with one single-cluster Wolff algorithm allied, in addition, with single histograms procedures and finite-size scaling techniques. Quite good fits to the experimental results of the ordering critical temperature, as a function of Al concentration in the range 0 ⩽ q < 0.7 , are obtained and compared to more recent theoretical approaches done on the same alloys. [ABSTRACT FROM AUTHOR]

In this work, we study the dielectric properties of a mixed spins (S = 5/2 and σ = 2) and (σ = 5/2 and S = 2) with Blume Capel model in a nanotube structure via Monte Carlo simulations for a several sizes. We start by discussing the ground state phase diagrams corresponding to several physical parameters. Then the polarizations have been analyzed. Besides, we explore the polarization behavior under the effect of the exchange coupling interaction and the crystal anisotropy fields. Furthermore, we investigate the presence of the compensation and critical temperatures resulted from the variation of the coefficient coupling and the crystal anisotropy field. Finally, the variation of the total polarizations as a function of the exchange coupling interaction, the crystal anisotropy field and the temperature have been discussed. • Dielectric properties of a mixed spins with Blume Capel model in a nanotube via Monte Carlo simulations. • Ground state phase diagrams of nanotube for a mixed spins were found. • Polarization behavior under effect of exchange coupling interaction and crystal anisotropy fields has been studied. • Compensation and critical temperatures of nanotube are found. • Hysteresis cycle in ferroelectric material are found in (E, P) plane. [ABSTRACT FROM AUTHOR]

We study the magnetic and thermodynamic properties of a spin- 1 ∕ 2 Ising system containing three layers, each of which is composed exclusively of one out of two possible types of atoms, A or B. The A-A and B-B bonds are ferromagnetic while the A-B bonds are antiferromagnetic. The study is performed through Monte Carlo simulations using the Wolff algorithm and the data are analyzed with the aid of the multiple-histogram reweighting technique and finite-size scaling tools. We verify the occurrence of a compensation phenomenon and obtain the compensation and critical temperatures of the model as functions of the Hamiltonian parameters. The influence of each parameter on the overall behavior of the system is discussed in detail and we present our results in the form of phase diagrams dividing the parameter space in regions where the compensation phenomenon is present or absent. Our results may provide invaluable information for experimentalists seeking to build materials with desired characteristics. • Ferrimagnetic spin-1/2 Ising trilayer is studied. • Each layer can only have atoms of one out of two types (A or B). • Only A-B couplings are antiferromagnetic. • Magnetic properties of the system are studied through Monte Carlo simulations. • Compensation phenomenon is found and phase diagrams are obtained. [ABSTRACT FROM AUTHOR]

• We study the magnetic and hysteretic properties of Graphene-Based Janus Materials using Monte Carlo calculations and mean field theory. • We show the effects of the number and the positions of dopants on thermodynamic quantities. • We give the conditions for the occurrence of compensation temperature. • We describe the influence of the system's parameters on the hysteresis curves. Based on our works [1–4] , we report the magnetic and hysteretic properties of graphene-based Janus materials namely, pure and doped zigzag graphone nanoribbons, hexagonal core/shell graphene-like nanoribbon, and graphyne core/shell nanoparticle, within the framework of both Monte Carlo calculations and mean field theory. We have reported the effects of the Hamiltonian parameters on the magnetic and the thermodynamic quantities of the systems. The total magnetization, the susceptibility, the specific heat, and the hysteresis curves, as well as the critical temperature and the compensation behavior, that is of crucial importance for technological applications such as thermo-optical recording, are studied. A number of characteristic behaviors are found, such as the existence of two new and non-classified magnetization profiles in addition to the Q -, P -, and N -types of compensation behavior and the occurrence of square, single, and triple hysteresis loops which exhibit different step effects and various shapes. [ABSTRACT FROM AUTHOR]

The critical, first order, and spin compensation behaviors of a ferrimagnetic Ising system, consisting of spins S = 3 ∕ 2 and Q = 5 ∕ 2 alternating on a square lattice, have been studied by Monte Carlo (MC) simulations and Mean-Field Theory (MF). The system is defined by a Hamiltonian (H) that contains ferromagnetic next-nearest-neighbors interactions between S spins (J 2 ′) and Q spins (J 3 ′), as well as external magnetic field (h ′) and anisotropy (D 1 ′ , D 2 ′) interactions. The effects of D 1 ′ crystal and h ′ magnetic fields on the critical, double first order transition, and compensation phenomena are analyzed in detail. We found that the existence of a double first order phase transition depends on the temperature and the strength of h ′. • We calculate the finite temperatura diagrams of the magnetization of the model. • The system exhibits compensation temperatures and first order transitions. • We analyze the relation between critical, compensation and first order temperatures. • The compensation temperatures and first order transitions depends of h' and D ' 1. [ABSTRACT FROM AUTHOR]