Ising Superlattice Research Articles

Effect of Ferromagnetic Exchange Interaction and Crystalline Anisotropy on a Double-Cubic Spin-½ Spin-1 Ising System with a Free Surface

In this study, we employ Monte Carlo simulations to explore the magnetic characteristics of a double-cubic spin-½ and spin-1 ferromagnetic Ising superlattice system, focusing on the impact of surface exchange coupling, anisotropy, and layer thickness. We implemented free boundary conditions along the dimension with an exposed surface. Our findings illuminate the key role played by surface exchange coupling (JAS), which significantly influences the critical temperature (Tc), underscoring its ability to strengthen ferromagnetic interactions within the system. In contrast, the compensation temperature (Tcomp) exhibits relative stability. Furthermore, we unveil the crucial influence of crystalline anisotropy on Tcomp, with higher anisotropy values leading to its augmentation, while Tc remains unaffected. Moreover, when the number of layers is increased from 11 to 21, a marked rise in Tc is observed, accompanied by a minor increment in Tcomp, particularly evident under negative anisotropy conditions.

Monte Carlo study on the compensation behavior and hysteresis properties of a ferrimagnetic superlattice with alternate layers

Based on Monte Carlo simulation, the magnetic properties of a mixed spin-1 and spin-3/2 Ising superlattice with alternate layers are studied. The effects of interlayer coupling and external magnetic field on the compensation behavior and hysteresis properties for the ferrimagnetic superlattice are investigated. The occurrence of a compensation point is found to be greatly affected by the interlayer coupling. In particular, various multiple hysteresis loops can be observed under certain system parameters. The calculated results agree well with available experimental and theoretical works.

Phase diagrams and magnetic properties of a superlattice with alternate layers

Abstract The phase diagrams and magnetic properties of an Ising superlattice are investigated by means of Monte Carlo simulation based on Metropolis algorithm. The system is formed by alternate layers of spins S = 1 and σ = 3 / 2 . The effects of the exchange coupling interactions and the crystal field on the phase diagrams and magnetic properties of the system are examined. A number of characteristic behaviors have been found. In particular, tricritical point, critical end point, and isolated critical point may occur in the present system.

Magnetic Properties of Spin-1/2 IsingSuperlattice

Using the effective-field theorywe studied the magnetic properties of aspin-1/2 Ising superlattice, which consist of three different ferromagnetmaterials. The magnetic behavior of this superlattice is examined. Thecritical temperature and the compensation temprature of the system arestudied as a function of the exchange interactions between thenearest-neiboring spins across the interface and in the intraface.Temperature dependence of magenetizations is also given.

The magnetizations and the phase transitions in the spin-1/2 Ising superlattice with impurities

The critical temperature of the spin-1/2 Ising superlattice with impurities is examined using the effective field theory with a probability distribution technique that accounts for the self-spin correlation functions. We discuss the effects of the interlayer and the intralayer exchange couplings, the concentration of magnetic atoms.

Phase diagrams of a spin-1 Ising superlattice

The three-dimensional spin-1 Ising superlattice consisting of two different ferromagnetic materials with two different crystal fields Δ 1 and Δ 2 is considered in the mean field approximation. The phase diagrams are considered in the ( t , d 2 ) plane for different ranges of variation of d 1 ( t = T / J , d 1 = Δ 1 / J , d 2 = Δ 2 / J are the reduced temperature and crystal fields respectively). The phase diagrams exhibit a variety of multicritical points and reentrant and double reentrant behaviours. They are found to depend qualitatively and/or quantitatively on the thicknesses of the materials in a supercell. This has direct consequences on the nature of the magnetic states of superlattices with different thicknesses.

The phase diagrams and the order parameters of the diluted transverse superlattice with antiferromagnetic interface coupling

Using the effective field theory with a probability distribution technique that accounts for the self-spin correlation functions, the magnetic properties of the Ising superlattice consisting of two ferromagnetic materials A and B, with L a layers of diluted spins S a= 1 2 and L b layers of diluted spins S b =1 in an applied transverse field Ω with antiferromagnetic interface coupling are examined. For fixed values of the reduced exchange interactions and the concentration c of magnetic atoms, the phase diagrams and the total magnetization for the superlattice are studied as a function of the transverse field and the temperature. We find a number of characteristic phenomena. In particular, the effect of the concentration c of magnetic atoms, the interlayer coupling and the transverse field on both the compensation temperature and the magnetization profiles are clarified. Some of them may be related to the experimental works of rare-earth (RE)/transition metal (TM) multilayer films.

The phase diagrams and the order parameters of the diluted superlattice with antiferromagnetic interface coupling

Using the effective field theory with a probability distribution technique that accounts for the self-spin correlation functions, the magnetic properties of the diluted Ising superlattice consisting of two ferromagnetic materials A and B, with L a layers of diluted spins S a= 1 2 and L b layers of diluted spins S b=1 with antiferromagnetic interface coupling are examined. For fixed values of the reduced exchange interactions and the concentration c of magnetic atoms, the phase diagrams, the two sublattice magnetizations and the total magnetization for the superlattice with the same spin S a=S b= 1 2 and for S a= 1 2 , S b =1 are studied as a function of the temperature. We find a number of characteristic phenomena. In particular, the effect of the concentration c of magnetic atoms, the interlayer coupling and the layer thickness on both the compensation temperature and the magnetization profiles are clarified.

Phase diagrams of a spin-1 Ising superlattice with alternating transverse field

The effects of alternating transverse fields Ω a and Ω b on the critical behavior of an alternating spin-1 Ising superlattice are studied within an effective field theory with a probability distribution technique that accounts for the single-site spin correlation. Critical temperatures are calculated as a function of the thickness of the superlattice and the strength of the transverse field. Depending on the values of the transverse fields Ω a and Ω b , the critical temperature can increase or decrease with increasing the thickness of the film, such result is not obtained in the uniform transverse field case ( Ω a = Ω b ). Furthermore, for each thickness L of the film, a long range ordered phase persist at low temperature for selected values of the transverse field Ω a and arbitrary values of Ω b . The effects of interlayer and intralayer exchange interactions are also examined.

The Ferromagnetic Spin-1 Ising Superlattice

The critical behavior of a ferromagnetic spin-1 Ising superlattice is studied using the effective field theory with a probability distribution technique that accounts for the self-spin correlation functions. The critical temperature of the system is calculated as a function of the exchange interactions in each material and the thickness of the constituents in a unit cell. A critical value of the interface exchange interaction above which the interface magnetism appears is found.

The Order Parameters of a Spin-½ Ising Superlattice in a Transverse Field

Using the effective-field theory with a probability distribution technique that accounts for the single-site spin correlations, the layer longitudinal magnetizations of the superlattice consisting of two different ferromagnets is examined in a transverse spin-½ Ising model. According to the values of the exchange interactions and the strength of the transverse field, we show that the interface magnetism may exist in the system and different types of phase diagrams are expected.

Phase diagrams of a transverse Ising superlattice based on two theoretical frameworks

The phase diagrams of a superlattice composed from two different alternating ferroelectric slabs with the same thickness L are discussed on the basis of the spin-1/2 transverse Ising model. The two theoretical frameworks of the differential operator technique are applied to the investigations, namely the Zernike approximation and the decoupling approximation superior to the Bethe–Peierls approximation. The unexpected phenomena obtained in the system with L=2, such as the reentrant phenomenon due to the competition of the interslab coupling and the transverse field, can be found by the use of both approximations. They seem to be independent of the theoretical approximation.

The ferromagnetic spin-1 Ising superlattice in a transverse field

The critical behavior of a ferromagnetic spin-1 Ising superlattice in a transverse field is studied using the effective field theory with a probability distribution technique that accounts for the self-spin correlation functions. The critical temperature of the system is calculated as a function of the exchange interactions in each material, the strength of the transverse field and the thickness of the constituents in a unit cell. A critical value of the interface exchange interaction above which the interface magnetism appears is found.

Phase transition properties of a ferroelectricspin-1/2 Ising superlattice

The phase transition properties of a ferroelectric superlatticedescribed by the Ising model in a transverse field have beeninvestigated using the effective-field theory with a probabilitydistribution technique that accounts for the self-spin correlationfunctions. An independent interface plane has been assumed and theparameters that imitate BaTiO3/SrTiO3 structure have been usedin our calculation. The Curie temperature, polarization, anddielectric constant have been obtained. The most striking featureis that the dielectric constant presents a maximum at roomtemperature. This kind of feature has been observed in a recentexperimental measurement.

Magnetic properties of the site-diluted spin-1 Ising superlattice

The critical behavior of a diluted spin-1 Ising superlattice is examined using the effective-field theory with a probability distribution technique that accounts for the self-spin correlation functions. The critical temperature of the system is studied as a function of the exchange interactions in each material, the concentration of magnetic atoms, and the thickness of the constituents in a unit cell. A critical value of the interface exchange interaction above which the interface magnetism appears is found. We calculated also some magnetic properties of a diluted spin-1 Ising superlattice such as the layer longitudinal magnetizations and quadrupolar moments. It is shown that the properties of the diluted system are different from those of the corresponding pure system.

The Influence of a Transverse Field on the Phase Diagrams for a Spin-½ Ising Superlattice

Using the effective field theory with a probability distribution technique that accounts for the single-site spin correlations, the critical behavior of a magnetic superlattice consisting of two different ferromagnets is examined in a transverse spin-½ Ising model. The critical temperature of the system as a function of the intralayer and interlayer exchange interactions is investigated for different cases. A critical value of the interface exchange coupling above which the interface magnetism appears is found. The effect of the transverse field on the behavior of the superlattice is clarified. We find a number of characteristic phenomena, such as the possibility of finding two critical interface exchange induced by the presence of the transverse field.

Critical properties of a spin-[formula omitted] Ising superlattice in transverse fields

Critical properties (transition temperature and critical transverse field) of a spin-12 Ising superlattice in transverse fields consisting of alternating two different slabs with same thickness L are investigated by the use of the effective-field theory. When the transverse field and the interslab exchange interaction are selected as large values, some characteristic (frustration) effects due to them can be obtained in the critical properties of the system with thin slab thickness (L≧2). They have not been predicted in many other works which discussed the same problem as the present one within the same approximation.

Monte-Carlo Study of Ising Model Ferromagnetic/Antiferromagnetic Spin Frustrated Superlattice

Conventional Monte-Carlo calculations have been carried out to simulate an N×N×N (N=10, 16, 20) Ising superlattice consisting of alternating layers of a ferromagnet and an antiferromagnet with different exchange interaction strengths in the antiferromagnetic layer. With increasing strength of the exchange interaction in antiferromagnetic layers, the ferromagnetic Curie temperature is decreased and the susceptibility is increased in superlattices. The magnetic susceptibility of the ferromagnetic layer is at its maximum value when the magnitudes of ferromagnetic interaction and antiferromagnetic interaction are equal.

Phase transitions in the spin-1/2 Ising superlattice with a transverse field

The phase transitions of a ferromagnet spin-1/2 Ising superlattice consisting of two different materials in a transverse field is examined with the use of the effective field theory that accounts for the self-spin function correlation. The critical temperature of the system is studied as a function of the thickness of the constituents in a unit cell and of exchange interactions in each material. A critical interface exchange interaction above which the interface magnetism appears is found. The effects of a uniform transverse field and the interface exchange interaction on the parameters of the system are also investigated.

Phase diagrams of the site-diluted spin-12Ising superlattice

Using the effective-field theory with a probability distribution technique that accounts for the single-site spin correlations, the critical behavior of a diluted spin-$\frac{1}{2}$ Ising superlattice consisting of two different ferromagnet materials is examined. The critical temperature of the system is studied as a function of the thickness of the constituents in a unit cell, the concentration of magnetic atoms, and the exchange interactions in each material. It is shown that the properties of the diluted system are different from those of the corresponding pure system.