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The mean-field approximation based on the Gibbs-Bogoliubov inequality and Monte Carlo simulations based on the Metropolis method in the Blume–Emery–Griffiths model were used to successfully examine a hexagonal Ising nanowire with spin-1. It was found that the model displays fascinating phase diagrams in various planes of interest by using both methods. The investigation of magnetic hysteresis cycles also exhibits interesting properties. The model not only presents first- and second-order phase transition lines, but also the tricritical and isolated critical points, multi-compensation temperatures, and magnetic hysteresis behavior with one to eight cycles. • The mean-field approximation based on the Gibbs-Bogoliubov inequality is applied. • The Monte Carlo simulations based on the Metropolis method is employed. • Spin-1 Blume–Emery–Griffiths model for hexagonal Ising nanowire is investigated. • First- and second-order transitions, tricritical and isolated critical points are found. • Multi-compensation and magnetic hysteresis with one to eight cycles are observed. [ABSTRACT FROM AUTHOR]

A mixed-spin (5/2, 3/2) Ising model is established to describe the antiferroelectric/ferroelectric (AFE/FE) BiFeO 3 /Co bilayer structure. We study the effects of the crystal field, exchange coupling and external longitudinal electric field on the dielectric properties of the bilayer based on Monte Carlo simulation. We illustrate the temperature dependence of polarization, susceptibility, internal energy and specific heat of the system in detail. As well, we depict the phase diagram and point out the rule of the blocking temperature with various parameters. In particular, we find rich and interesting multi-cycle electric hysteresis behaviors. The results show that these parameters play a crucial part in the physical properties of the AFE/FE BiFeO 3 /Co bilayer structure. [ABSTRACT FROM AUTHOR]

• Ferrimagnetic mixed spin (3/2,1) Ising for zigzag and armchair graphene-like nanoribbons (GNRs) is investigated using the finite cluster approximation FCA. • Transition reentrance is revealed for both GNRs for lower J co strength. • Double compensation points are identified for the armchair GNR under the effect of the shell crystal field. • The core crystal field may lead for both zigzag and armchair GNRs, to a tricritical behavior. Graphene-like nanoribbon structures (GNRs) in which singular magnetic properties emerge because of the graphene-cutting process, may offer unique opportunities for future technological development such as spintronics. Using the finite cluster approximation, research has been implemented on some magnetic and critical characteristics of a mixed spin-3/2 and spin-1 Ising ferrimagnetic graphene-like nanoribbon with two typical edges, namely armchair, and zigzag. We investigate the influences of such aspects as crystal fields, exchange couplings, and temperature on phase diagrams and magnetizations. Tricritical as well as compensation behaviors have been demonstrated under the effect of the above physical parameters. In particular, only armchair GNR may exhibit double compensation points. Meanwhile, an unexpected reentrant transition has been discovered for both GNRs, which is mainly due to the finite size effect. [ABSTRACT FROM AUTHOR]

In this work, the Effective Field Theory (EFT) based on the probability distribution method is used to study the phase diagrams of an antiferroelectric nanowire with core/shell morphology, in the presence of a random transverse field. We have investigated the effects of the temperature, the concentration c , the surface and the interfacial couplings on the critical and the compensation behaviors (T c and T comp) of the system. The polarization, the susceptibility and the pyroelectric coefficient as a function of the temperature are examined. In addition, the phase diagrams of the nanowire are investigated in detail by modifying the system parameters. It is found that the interfacial coupling | J int / J c | shifts the random transverse field to higher values, therefore the area of the ordered phase is enlarged, which could affects the critical and the compensation temperatures. • The phase diagrams of a nanowire with antiferroelectric interfacial coupling are examined by the effective field theory. • The effect of the antiferromagnetic interfacial coupling on the critical and the compensation behaviors is studied. • The influence of the random transverse field on electric properties. • The dependence of the polarization, pyroelectric coefficient and susceptibility on the temperature are investigated. [ABSTRACT FROM AUTHOR]

In this paper, the ferrimagnetic mixed-spin (3/2, 5/2) Ising model was established to investigate the magnetic and thermodynamic properties of a nanoisland bilayer system with graphene-like structure by Monte Carlo simulation. We have analyzed the magnetization of the system and two sublattices, susceptibility, internal energy and hysteresis loops in detail. We have obtained the phase diagrams of the blocking temperature T B affected by the effects of various physical parameters. The triple hysteresis behavior has been observed, which originates from the competition among various physical parameters. Our results are comparable with those of other theoretical and experimental research. • The ferrimagnetic mixed-spin (3/2, 5/2) graphene-like nanoisland bilayer in the longitudinal magnetic field has been investigated. • Magnetization, susceptibility and internal energy have been discussed. • The phase diagrams of blocking temperature have been obtained under the influence of various physical parameters. • The triple hysteresis behavior have been found for certain physical parameters. [ABSTRACT FROM AUTHOR]

In this work, we study the magnetic properties of a borophene core-shell structure with spins σ = 5/2 and S = 3/2, using Monte Carlo simulations. 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 reduced exchange coupling interactions. Furthermore, we investigate the presence of the compensation temperature induced by the presence of a core shell structure and resulted from the variation of the reduced coefficient coupling. Finally, the variation of the total magnetizations as a function of the reduced exchange coupling interactions, the crystal and the external fields has been discussed. • Monte Carlo Simulations is used to investigate the magnetic properties of the core-shell Borophene. • The ground state phase diagrams are established. • The effect of exchange coupling interactions and magnetic external and crystal fields are analyzed. • The existence of compensation Temperature is studied. • The hysteresis cycles are explored. [ABSTRACT FROM AUTHOR]

Magnetic properties of a superlattice that consists of three square layers with Ising spins σ = 1 / 2 , s = 1 and q = 5 / 2 , are investigated by means of standard Monte Carlo simulations and Mean Field Theory. The Hamiltonian model comprises contributions of intralayer and interlayer exchange interactions and the applied external magnetic field. Effects of the external magnetic field on magnetic behaviors have been thoroughly studied in the presence of thermal excitation. Ground state and thermal phase diagrams are numerically computated by both methods. Ground state phase diagrams of the system exhibit one ferromagnetic phase (1/2, 1, 5/2) and three ferrimagnetic ones: (−1/2, 1, 5/2), (−1/2, −1, 5/2) and (−1/2, 1, −5/2). A number of interesting phase diagrams and phenomena have been found, including hysteresis behaviors. [ABSTRACT FROM AUTHOR]

The double perovskite Sr2CrIrO6 has very important characteristics for spintronic applications. It is a ferrimagnetic material distinguished by its high Curie temperature. This manuscript presents a model representing the double perovskite Sr2CrIrO6 in order to simulate and to predict its magnetic properties. This compound contains only two magnetic atoms, namely: Cr (S = 3/2) and Ir (σ = 2). Our simulations are done using the Monte Carlo method under the Metropolis algorithm. We present the behavior of the magnetization and the susceptibilities as a function of the temperature. Also, we discuss the effect of the physical parameters such as the coupling exchange interactions, the crystal field and the external magnetic field. To complete this study, we have presented the ground state by exposing the different phase diagrams in different planes of the physical parameters. Moreover, we establish the magnetic hysteresis loops of this compound. • We study the magnetic properties of the double perovskite Sr2IrCrO6. • We perform Monte Carlo simulations to investigate the magnetic properties of the double perovskite Sr2IrCrO6. • The effect of the physical parameters is studied and discussed. • The hysteresis loops are also presented for specific values of the physical parameters. [ABSTRACT FROM AUTHOR]

Highlights • Magnetic H - T phase diagram of a Fe/Gd ferrimagnetic superlattice is obtained. • Collinear, twisted and surface twist magnetic states are identified. • Two spectral branches of ferromagnetic resonance are observed. • The observed modes correspond to different types of non-uniform precession in Gd. Abstract Static and dynamic magnetic properties of a ferrimagnetic Fe (35 Å) / Gd (50 Å) 12 superlattice were investigated in a wide 4–300 K temperature range using magneto-optical Kerr effect (MOKE) and ferromagnetic resonance (FMR) techniques. The multilayer structure was sputtered on a transparent glass substrate which made it possible to perform MOKE measurements on both Fe and Gd terminated sides of the superlattice. These experiments allowed us to detect a transition between field-aligned and canted magnetic states on both sides of the film and to distinguish between the bulk and surface twisted phases of the superlattice. As a result, the experimental H - T magnetic phase diagram of the system was obtained. FMR studies at frequencies 7–36 GHz demonstrated a complex evolution of absorption spectra as temperature decreased from room down to 4 K. Two spectral branches were detected in the sample. Theoretical simulations show that the observed spectral branches correspond to different types of inhomogeneous resonance modes in the multilayer with non-uniform magnetization precession inside Gd layers. [ABSTRACT FROM AUTHOR]

Abstract The ferrimagnetic-ferromagnetic-ferrimagnetic quaternary alloy is constructed on the Bethe lattice in the compound form as AB p C q D r and formulated in terms of the exact recursion relations in the standard-random approach. The QA is designed on the BL by placing the A atoms (spin-1) only on the sites of odd shells and randomly placing B (spin-3/2), C (spin-5/2) or D (spin-2) atoms with probabilities, or concentrations, p , q and r , respectively, on the sites of even shells. The phase diagrams are obtained from the thermal analysis of the order-parameters. It is also found that the model yields only one compensation temperature. Highlights • The ferrimagnetic‐ferromagnetic‐ferrimagnetic quaternary alloy (QA) is constructed on the Bethe lattice. • The QA is taken in the compound form as ABpCqDr and formulated in terms of exact recursion relations. • The randomization is applied in the standard‐random approach. • The A, B, C and D atoms are taken as spin‐1, spin‐3/2, spin‐5/2 and spin‐2, respectively. • The phase diagrams are studied from the thermal analysis of the order‐parameters. [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 proposed a ferrimagnetic mixed-spin (1, 3/2) Ising model to study the magnetic behaviors of a graphene ladder-type chain structure by means of Monte Carlo simulation. Induced by different physical parameters, the system can display interesting magnetic behaviors such multiple saturation magnetization values, double-peak susceptibility curves, and multi-cycle hysteresis loops. The results illustrate that crystal-field, exchange coupling and external magnetic field show significant impacts on the magnetic properties of the system. • A mixed-spin (1, 3/2) Ising model was proposed to describe a ferrimagnetic graphene ladder-type chain structure. • Magnetization, magnetic susceptibility, and internal energy were studied by Monte Carlo method. • The phase diagrams of the blocking temperature in three-dimensional space was given. • Multi-cycle hysteresis behaviors were discovered caused by various parameters. [ABSTRACT FROM AUTHOR]

Compensation temperature T comp and transition temperature T C have significant applications for the experimental realization of magnetic nanotube structure in the field of thermal magnetic recording. In this work, we use the Monte Carlo simulation to investigate the phase diagrams, magnetizations, susceptibilities, internal energies, specific heats and hysteresis behaviors of a cylindrical ferrimagnetic nanotube with core-shell structure. The effects of the single-ion anisotropies ( D C , D S ) and the exchange couplings ( J int , J S ) on the magnetic and thermodynamic properties of the system are examined. A number of characteristic behaviors are discovered in the thermal variations, depending on different physical parameters. In particular, the triple hysteresis loops behavior has been found for appropriate physical parameters. These findings are qualitatively in good agreement with related experimental and the other theoretical results. [ABSTRACT FROM AUTHOR]

Monte Carlo simulation has been used to study magnetic and thermodynamic properties of a ferrimagnetic mixed-spin (1, 3/2) Ising nanowire with hexagonal core-shell structure. The ground phase diagrams are obtained for different exchange couplings. The critical values of the exchange couplings have been found, determining whether the compensation points appear in the present system. In particular, the effects of the exchange couplings and the temperature on the magnetization, the internal energy, the specific heat, the compensation points and hysteresis loops are discussed in detail. Under certain physical parameters, multiple cycle hysteresis loops such as triple and quintuple hysteresis loop patterns have been observed in the system. It is found that the exchange coupling and the temperature strongly affect the coercivity and the remanence of the system. Compared our results with other theoretical and experimental studies, a good agreement has been obtained qualitatively. [ABSTRACT FROM AUTHOR]

By using Monte Carlo simulations for classical Heisenberg spins, we study the critical phenomena and ferrimagnetic properties of spherical nanoparticles with core-shell geometry. The particle core is composed of ferromagnetic spins, and it is coated by a ferromagnetic shell. Total size of the particle is fixed but the thickness of the shell is varied in such a way that the shell layer is grown at the expense of the core. Effects of the shell thickness, as well as dynamic magnetic field parameters such as oscillation period and field amplitude on the magnetization profiles, dynamic hysteresis loops and phase diagrams have been investigated for the present system. It has been found that as the shell thickness varies then the easy axis magnetization of the overall system may exhibit Q -, P -, L - and N - type behaviors based on the Neél terminology. We also found that three distinct anomalies originate in the thermal variation of specific heat with increasing field period. Dynamic hysteresis loops corresponding to off-axial magnetization components exhibit unconventional behavior such as double rings with symmetric shapes around the vertical axis over the h ( t ) = 0 line which may originate due to the stochastic resonance behavior of these components. [ABSTRACT FROM AUTHOR]

A hexagonal nanowire consisting of a ferromagnetic spin– 1 2 core and spin– 3 2 outer shell coupled with ferrimagnetic interlayer coupling has been studied by the use of the Monte Carlo simulation based on the heat bath algorithm. Particular emphasis is given to the effects of the size, the crystal field, the shell and the interface coupling constants on the critical and the compensation phenomenon. Some interesting behaviors have been observed which include the first and second order phase transitions. The isolated critical points are also observed. We have also found that the system exhibits the compensation phenomenon for appropriate values of the system parameters. The critical exponent has also been calculated. [ABSTRACT FROM AUTHOR]

We investigate magnetic quantum phases and the topological quantum phase transition between two distinct valence-bond solid (VBS) phases of a minimal interacting spin-chain model that captures a magnetic behavior of the novel low-dimensional quantum ferrimagnetic material Cu 2 Fe 2 Ge 4 O 13. The studied mixed-spin Heisenberg tetramer chain consists of a 4-period array of spins involving two types of dimers s a − s a ( s a = 1 / 2) and S b − S b ( S b = 5 / 2) under the assumption of unique intra- and inter-dimer coupling constants J 1 and J 2 , respectively. Using the tensor-network formulation of the density-matrix renormalization group method, we have constructed the ground-state phase diagram in the parameter space magnetic field versus the interaction ratio J = J 2 / J 1 , whereby all ground states are in accordance with the Oshikawa–Yamanaka–Affleck theorem for a given period. In addition, we have implemented the recent tangential finite-size scaling method in order to characterize the critical behavior of the topological VBS transition through calculation of the critical point J c and the critical exponent of the correlation length ν. Our results are consistent with the topological quantum phase transition from the SU(2) Wess–Zumino–Witten universality class with the critical exponent of correlation length ν = 2 / 3 by assuming the proper logarithmic correction. • A tetramer ferrimagnetic spin chain with alternate exchange couplings is considered. • The ground-state phase diagram presents magnetization plateaus and spin-liquid phases. • The system presents a topological quantum phase-transition at zero field. • The zero-field transition is between trivial and non-trivial topological phases. • A finite-size analysis unveils a logarithmic correction to the power-law scaling. [ABSTRACT FROM AUTHOR]

The phase diagrams and the magnetic properties of a spherical ferrimagnetic nanoparticle, consisting of a ferromagnetic core of atoms A with spin-1/2 ( S A = 1 / 2 ) surrounded by a disordered ferrimagnetic binary alloy shell of two kinds of atoms ( A and B ) with different spins ( S A = 1 / 2 and S B = 3 / 2 ) are studied by using Monte Carlo simulation based on the Metropolis algorithm. Depending on the values of the Hamiltonian parameters, the system presents a number of outstanding phenomena, such as the possibility of one, two or even three compensation point(s). The existence of a compensation temperature is an interesting phenomenon with important technological applications in the field of thermomagnetic recording. [ABSTRACT FROM AUTHOR]

The hysteresis properties and phase diagrams of a ternary nanowire, composed of a ferromagnetic (FM) core of spin-1 encircled by a ferrimagnetic (FiM) shell of mixed spin-(1/2, 3/2). Monte Carlo simulation is used to study the effects of the exchange interactions (R s , R 1 , R 2 and R I F) and crystal fields (D c , D s) on the phase diagrams for various thicknesses of core and shell of the system. Our outcomes indicate that the compensation temperature exists for a particular range when D c and D s are present. In addition, a first and a second order phase transitions appear for different values of D c , while a second phase transition appears for various values of D s. Moreover, the hysteresis loops, coercivities and remanences of the system and three sublattices are discussed in detail. Multiple hysteresis loops such as double, triple and quintuple loops were found in the system for a various physical parameters. By comparing our findings to those of previous theoretical and experimental studies, a qualitative agreement can be found. [ABSTRACT FROM AUTHOR]

• A multi-walled mixed spin (1/2; 1; 1/2; 1) Ising nanowire with a basic hexagonal shape is built. • For ferrimagnetic and ferromagnetic sates, different magnetic properties are established. • The magnetization types and compensating behaviors are strongly influenced by different Hamiltonian settings. • Unique outcomes are discovered. Using the Effective Field Theory with correlation, we investigate the magnetic properties and the phase diagram of a mixed-spin (½, 1, ½, 1) Ising core-multi shell nanowire structure. Typical temperature dependence of the total magnetization, the core and shell magnetization for several fixed values of exchange couplings were discussed in detail. The phase diagrams of the critical and compensation temperatures were displayed in various Hamiltonian parameter planes. Our established results have been successfully compared with results from several experimental and theoretical studies. The ultimate objective is to stimulate research into the design and development of innovative nanomaterials for targeted applications. [ABSTRACT FROM AUTHOR]

The phase diagrams and magnetizations of Ising nanowires with simple core–shell structure are investigated by the use of the effective field theory with correlations. A lot of characteristic behaviors observed in ferromagnetic and ferrimagnetic materials as well as novel phenomena have been obtained, although one section of the system is consisted of one spin-1/2 surface shell atom and one spin-1/2 core atom and they are coupled with a positive or a negative shell–core exchange interaction. [ABSTRACT FROM AUTHOR]

Within the effective-field theory (EFT), the compensation behaviors in molecular-based ferrimagnet A F e Ι Ι F e Ι Ι Ι ( C 2 O 4 ) 3 which is described by a mixed spin-2 ( F e Ι Ι ) and spin-5/2 ( F e Ι Ι Ι ) ferrimagnetic Ising model on a honeycomb lattice are studied. The Glauber-type stochastic dynamic is used to describe the time evolution of the system under an oscillating magnetic field. A magnetic field dependence of the compensation temperature and a temperature dependence of compensating magnetic field are calculated and both curves agree qualitatively with experimental data. In particular, a two-compensation-points phenomenon which has been reported in the experimental work is also observed in this compound. Dynamic phase boundaries containing the compensation points are calculated. The dynamic tricritical point and critical end point exist on the phase transition lines. Comparing with previous theoretical results obtained by the mean-field theory (MFT), the effective-field theory results show a reasonable improvement over the MFT results. [ABSTRACT FROM AUTHOR]

We performed the Monte Carlo simulation (MCs) in order to study the magnetic properties and the critical behavior of Sr 2 CrMoO 6 . Within this magnetic oxide, the Cr 3+ and Mo 5+ ions form two interpenetrating ferromagnetic sublattices with opposite spins directions (Cr 3 + up and Mo 5+ down). The exchange interaction between these sublattices is assumed to be ferrimagnetic. The effects of the system parameters on critical temperatures and as a result on the phase diagrams are shown by using reduced values of parameters. The phase transitions and the magnetic stability are investigated in the framework of Ising model. For specific values of the system parameters, the existence of a compensation point is shown. Furthermore, to investigate the critical behavior, the critical exponents are calculated, they indicate that the compound belongs to a three dimensional Ising universality class. The reduced transition temperature is also found. [ABSTRACT FROM AUTHOR]

In this study we used the path probability method (PPM) to calculate the dynamic phase diagrams of a ferrimagnetic mixed spin-(1/2, 1) Ising system under an oscillating magnetic field. One of the main advantages of the PPM over the mean-field approximation and the effective-field theory based on Glauber-type stochastic dynamics is that it contains two rate constants which are very important for studying dynamic behaviors. We present the dynamic phase diagrams in the reduced magnetic field amplitude and reduced temperature plane and the twelve main different topological types of the phase diagrams are obtained. The phase diagrams contain paramagnetic (p), ferrimagnetic (i) and i + p mixed phases. They also exhibit a dynamic tricritical and reentrant behavior as well as the dynamic double critical end point (B), critical end point (E), quadruple point (QP) and triple point (TP). The dynamic phase diagrams are compared and discussed with the phase diagrams obtained in previous works within the mean-field approximation and the effective-field theory based on Glauber-type stochastic dynamics. [ABSTRACT FROM AUTHOR]

The effective-field theory with correlations based on Glauber-type stochastic dynamic is used to study the dynamic compensation behavior of the mixed spin-1 and spin-3/2 ferrimagnetic Ising model. The system is a layered honeycomb structure in which two kinds of spins (spin-1 and spin-3/2) occupy sites alternately. This is related to the experimental works of a molecular-based magnetic multilayer film, AM II Fe II ( C 2 O 4 ) 3 ( A = N ( n − C n H 2 n + 1 ) 4 , M II = Mn,Fe ) . The system is in the presence of a sinusoidal oscillating magnetic field and the Glauber dynamic is used to describe the time evolution of the system. The effects of the interlayer coupling and a crystal-field constant of the spin-1 sublattice on the compensation temperature are investigated. Dynamic phase diagrams, including the compensation points are presented. Besides second-order phase transition, lines of first-order phase transition, the dynamic tricritical point, the dynamic zero-temperature critical point and the multicritical point are found. The dynamic tricritical point, the dynamic compensation point and the non-magnetic phase predicted by the mean-field theory are confirmed by the effective-field theory. [ABSTRACT FROM AUTHOR]

In this work, a Monte Carlo simulation, based on standard Metropolis algorithm, has been applied to investigate magnetic properties of a ferrimagnetic nanoparticle, with a cubic shape and core–shell structure. The nanoparticle is constituted of spin-1/2 in the core surrounded by spin-3/2 in the shell. It has been shown that the exchange coupling plays an important role on the phase diagrams. Some interesting features have been observed for the temperature dependence of total magnetization curves of particle. In particular, the effects of the interface coupling and the shell coupling on both the compensation temperature and the magnetization profiles are investigated. In addition, the effect of the single ion anisotropy as well as the hysteresis loops behavior has also been discussed in detail. [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]

Abstract: In this work, we have used Monte Carlo Simulation technique (MCS) and effective field theory (EFT) to study the critical and the compensation behaviors of a ferrimagnetic cylindrical nanowire. The system consists of a ferromagnetic spin S A =1/2 core and a ferromagnetic spin S B =1 surface shell coupled with an antiferromagnetic interlayer coupling J 1 to the core. The effects of the uniaxial anisotropy, the shell coupling and the interface negative coupling on both the critical and compensation temperatures are investigated. [Copyright &y& Elsevier]

Abstract: We address the possibility of spiral ferrimagnetic phases in the mean-field phase diagram of the two-dimensional (2D) Hubbard model. For intermediate values of the interaction U ( ) and doping n, a spiral ferrimagnetic phase is the most stable phase in the (n,U) phase diagram. Higher values of U lead to a non-spiral ferrimagnetic phase. If phase separation is allowed and the chemical potential replaces the doping n as the independent variable, the phase diagram displays, in a considerable region, a spiral (for ) and non-spiral (for higher values of U) ferrimagnetic phase with fixed particle density, n=0.5, reflecting the opening of an energy gap in the mean-field quasi-particle bands [Copyright &y& Elsevier]

Abstract: A Monte Carlo Simulation has been used to study the critical behavior of the magnetic spin-1 Ising nanowire on an hexagonal lattice structure. Our system consists of a ferromagnetic core with two shells, coupled antiferromagnetically with a surface shell. The effects of the crystal field, the shell and the core/shell interactions on the behavior of the system are examined. We found that the system exhibits one or two compensation points, the first and the second order transitions. Moreover, we have obtained that the critical point depends on the shell coupling. [Copyright &y& Elsevier]

Abstract: We study the effect of two different single-ion anisotropies in the phase diagram and in the compensation temperature of mixed spin-2 and spin- Ising ferrimagnetic system. We employed the mean-field theory based on the Bogoliubov inequality for Gibbs free energy. We use the Landau expansion of free energy in the order parameter to describe the phase diagram. In the temperature versus single-ion anisotropy plane the phase diagram displays tricritical behavior. The critical and compensation temperatures increase with increasing values of the single-ion anisotropies. [Copyright &y& Elsevier]

The ability to combine multiple spintronic properties in the Zn x Fe 3- x O 4 system with different variants of its chemical composition offers a new and tantalizing route towards homodevices. This is mainly due to the advantage of varying the Zn component of Zn x Fe 3- x O 4 , which leads to the possibility of preserving spinel symmetry (within 5% lattice mismatch) while changing the material properties from a ferrimagnetic half-metal (x = 0) to an insulating paramagnet (x = 1). Here we demonstrate that Zn x Fe 3- x O 4 thin films, grown from a ZnFe 2 O 4 single phase target, laser-ablated under a reduced atmosphere, exhibits a reduction of Zn content, a large 4πM S (6.5 kG), very low resistivity (25 mΩ cm) and a Verwey transition, all of which can be engineered by an appropriate choice of growth temperature. All these spectacular properties are confirmed by ab initio calculations and can be attributed to the inverse structure of [Zn x +2Fe 1−x +3] A [Fe 1+y +3Fe 1−y +2] B O 4-δ , where the reduced Fe+2 ions along with Fe+3 occupy the octahedral sites while the Zn+2 and inverted Fe+3 sit in the tetrahedral sites. Phase formation in laser ablated Zn x Fe 3- x O 4 thin films are different compared to the bulk thermal equilibrium, and shows that there is a competition between the reduction of Zn and the formation of O vacancies at various growth temperature zones. • Stabilization of ferrimagnetic phase in Zn x Fe 3- x O 4-δ thin films which otherwise difficult. • Observation of all in one spintronic properties (high M, low ρ and half metallicity). • Construction of growth phase diagram of Zn x Fe 3- x O 4-δ and Fe 3 O 4-δ thin films. • DFT calculation of inverted spinel Zn x Fe 3- x O 4-δ for its elusive electro-magnetic properties. [ABSTRACT FROM AUTHOR]

Monte Carlo simulation has been employed to investigate the magnetic properties and phase diagrams of ferrimagnetic mixed-spin (1 / 2 , 1) triangular Ising nanotube with core–shell structure. In particular, the effect of the exchange couplings and the temperature on the magnetic and thermodynamic properties, hysteresis loops, and the compensation temperature have been discussed in detail. Moreover, the effects of the single-ion anisotropy and external magnetic field have been examined. The threshold values of the exchange couplings and single-ion anisotropy have been found, determining whether the system exhibits a compensation temperature. We have found that the appearance of the compensation temperature is strongly linked with the system parameters. Moreover, we have obtained the double and triple hysteresis loops for certain physical parameters in the magnetic system. [ABSTRACT FROM AUTHOR]

• The graphene-like quantum dots with mixed-spin (3/2, 5/2) have been investigated. • The magnetic and thermodynamic behaviors have been explored. • The turnover phenomenon has been found. • The triple-loop behavior has been observed. Based on the Monte Carlo simulation, we have investigated the magnetic and thermodynamic behaviors of the graphene-like quantum dots described by a ferrimagnetic mixed-spin (3/2, 5/2) Ising model. The curves of the magnetization, magnetic susceptibility, internal energy and the specific heat as a function of temperature have been given under various physical parameters. The interesting turnover phenomenon has been found owing to the competition between the crystal field and temperature. It is found that the value of the blocking temperature increases with decreasing the crystal field or increasing the exchange coupling and external magnetic field. We have also investigated the hysteresis loops and found the impossibility of the triple-loop hysteresis behavior for certain parameters. The area of the hysteresis loops can be improved by increasing the exchange coupling and decreasing the absolute values of the crystal field and temperature. [ABSTRACT FROM AUTHOR]

• Dynamic phase transitions of the mixed spin (1/2, 3/2) system are investigated by the path probability method. • The system undergoes two successive phase transitions in some cases. • The system exhibits one or two dynamic tricritical and double critical end points. • The system contains the paramagnetic, ferrimagnetic and mixed phases. • The system displays reentrant behavior for certain interaction parameter. Dynamic phase transitions (DPTs) of the mixed spin (1/2, 3/2) Ising ferrimagnetic model on the two interpenetrating square lattice with the bilinear and crystal-field interactions under a time-varying (sinusoidal) magnetic field were examined by using the path probability method (PPM). We studied stationary solutions of dynamic average magnetizations and obtained phases and then we investigated thermal behaviors of dynamic magnetizations to designate the nature of the DPTs and find the DPT temperatures. We also constructed the dynamic phase diagrams (DPDs) in two different planes. DPDs exhibit the paramagnetic (p), ferrimagnetic (i), and mixed phases (i + p), and one or two dynamic tricritical points and dynamic double critical end points. The reentrant behavior is also seen. We observed that the PPM is a more appropriate dynamic method to study the dynamic features of ferrimagnetism. [ABSTRACT FROM AUTHOR]

• Ferrimagnetic mixed spin systems on body-centered cubic recursive lattice are studied exactly. • The existence of new intermediate phase is predicted in all investigated models. • The second-order nature of all phase transitions is shown and all phase diagrams are found. • All possible series of consecutive phase transitions are identified and discussed. • Magnetization properties of all phases of studied models are investigated in detail. Using the recursive lattice technique the existence of the intermediate phase, which separates two ferrimagnetic phases in the 1 / 2 − σ (σ = 1 , 3 / 2 , 2) mixed-spin Ising ferrimagnets with the presence of the next-to-nearest neighbor interaction on the regular body-centered cubic lattice, is predicted. It is shown that, for given spin value of the central sites of the body-centered cubic lattice, this intermediate phase is realized in the corresponding narrow interval of the values of the frustration parameter of the model, that the form of the region, where the intermediate phase exists, depends on the value of the central spin σ (becomes larger with increasing of σ), and that all transitions between various phases of the model always have the second order nature. All possible series of consecutive phase transitions of the model are identified and the properties of the sublattice magnetizations are studied and discussed in detail. [ABSTRACT FROM AUTHOR]

Spin-1/2 orthogonal-dimer chain composed of regularly alternating Ising and Heisenberg dimers is exactly solved in a presence of the magnetic field by the transfer-matrix method. It is shown that the ground-state phase diagram involves in total six different phases. Besides the ferromagnetic phase with fully polarized spins one encounters the singlet antiferromagnetic and modulated antiferromagnetic phases manifested in zero-temperature magnetization curves as zero magnetization plateau, the frustrated ferrimagnetic and singlet ferrimagnetic phases causing existence of an intermediate one-half magnetization plateau, and finally, the intriguing modulated ferrimagnetic phase with a translationally broken symmetry leading to an unconventional one-quarter magnetization plateau. The quantum character of individual ground states is quantified via the concurrence, which measures a strength of the bipartite entanglement within the pure and mixed states of the Heisenberg dimers at zero as well as nonzero temperatures. The parameter region, where the bipartite entanglement may be in contrast to general expectations reinforced upon increasing of temperature and/or magnetic field, is elucidated. [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]

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]

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]

The nonequilibrium magnetic properties (phase transition temperatures, phase diagrams, hysteresis loop areas and correlations) are investigated in the kinetic mixed spin (1/2, 1) Ising nanowire system under the time varying magnetic field. The Glauber-type stochastic dynamics are employed to construct the set of mean field dynamic equations. The time variation of the core/shell magnetizations and the thermal behavior of the dynamic core/shell magnetizations are examined, extensively. The dynamic core/shell magnetizations, hysteresis loop areas and correlations are studied as a function of temperature in order to characterize the nature (continuous or discontinuous) of the phase transitions as well as to find the dynamic phase transition temperatures. The dynamic phase diagrams are presented in the magnetic field amplitude and temperature plane. The dynamic phase diagrams exhibit paramagnetic (p), ferrimagnetic (i), nonmagnetic (nm) phases, three mixed regions, (i + nm), (i + p) and (nm + p). The dynamic phase diagrams contain a dynamic tricritical point and reentrant phenomena, which strongly depend on interaction parameters. • Nonequilibrium magnetic properties of Ising nanowire are investigated. • The Glauber-type stochastic dynamics are employed to construct the set of mean field dynamic equations. • The dynamic phase diagrams are presented in the magnetic field amplitude and temperature plane. • The dynamic phase diagrams contain a dynamic tricritical point and reentrant phenomena. [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]

• The two (A and B) Ising nanoparticles are investigated. • They are discussed by using the effective-field theory with correlations. • The phase diagrams and magnetizations are obtained. • Some characteristic phenomena, such as the reentrant phenomena and ferrimagnetic behaviors, are found. The phase diagrams and magnetization curves of two antiferromagnetic Ising nanoparticles (A and B) under an applied transverse field are investigated by using the effective-field theory with correlations. The nanoparticle B is a size larger than that of nanoparticle A. The effects of size on the magnetic properties are discussed. Some characteristic features, such as the reentrant phenomena, are found in these properties of both systems, when a finite transverse field h is applied. The nanoparticle B exhibits the ferrimagnetic behaviors, such as a compensation point. [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]

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]

In this paper, we proposed a ferrimagnetic mixed-spin (1, 3/2) Ising model to describe the ladder-like graphene nanoribbon. Using the Monte Carlo simulation, the effects of the anisotropies, exchange couplings, longitudinal magnetic field and temperature on the magnetic and thermodynamic properties were investigated. Typical temperature dependences of thermodynamics quantities such as magnetization, susceptibility and internal energy were presented under the influence of various physical parameters. The phase diagrams of blocking temperature were obtained in the different parameter planes. In particular, we also found some interesting double hysteresis loops behavior for certain physical parameters. Our results are consistent with those obtained by some theoretical and experimental researches. • The ferrimagnetic mixed-spin (1, 3/2) Ising ladder-like graphene nanoribbon in the longitudinal magnetic field has been studied. • Magnetization, susceptibility and internal energy have been discussed. • The phase diagrams of the blocking temperature under the influence of different parameters have been obtained. • The double hysteresis loops behavior has been found for certain physical parameters. [ABSTRACT FROM AUTHOR]

In this work, we have investigated a ferrimagnetic mixed-spin (2, 5/2) Ising nanoisland with bilayer graphene-like structure within the framework of Monte Carlo simulation. The unique magnetic and thermodynamic behaviors of the system have been revealed under the effects of the Hamiltonian parameters and temperature. We obtain the phase diagrams of the blocking temperatures and discontinuous points. For certain parameters, there are rich multiple-cycle hysteresis behaviors, which is caused by competition among various Hamiltonian parameters. Some results obtained can be compared with other theoretical and experimental studies. • A ferrimagnetic mixed-spin (2, 5/2) graphene-like Ising bilayer nanoisland is proposed. • The magnetization, the susceptibility and the internal energy are studied by Monte Carlo simulation. • Effects of next-nearest-neighbor and next-next-nearest-neighbor intralayer exchange couplings are investigated. • The phase diagrams of the blocking temperatures and discontinuous points in different parameter planes are obtained. • Multiple-cycle hysteresis loops behaviors are discovered for certain values of physical parameters. [ABSTRACT FROM AUTHOR]

The Monte Carlo simulation has been applied to study the magnetic behaviors of a ferrimagnetic mixed-spin (1, 2, 5/2) Ising nanoisland with bilayer hexagonal core-shell structure in an external longitudinal magnetic field. We have investigated the influences of the anisotropies, the exchange couplings, the longitudinal field and temperature on magnetization, susceptibility, internal energy and hysteresis loop of the present nanoisland. The behavior of the X parameter (the magnetization, susceptibility, internal energy and blocking temperature) as a function of the parameter is studied. Particularly, the multiple hysteresis loop behaviors have been discovered, such as triple, quintuple, septuple, ninefold and elevenfold hysteresis loops under certain physical parameters. • A ferrimagnetic mixed-spin (1, 2, 5/2) Ising nanoisland with bilayer hexagonal core-shell structure is proposed. • The magnetization, the susceptibility and the internal energy are studied by Monte Carlo simulation. • The phase diagrams of the blocking temperature in different parameter planes are obtained. • The multiple hysteresis loop behaviors are found for certain values of physical parameters. [ABSTRACT FROM AUTHOR]