Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Phase Transitions

Phase diagrams in an ultra-thin spin-1 transverse Ising film with bond or site dilution at surfaces

T. Kaneyoshi

Published Apr 29, 2013• 11 citations
Publisher

Abstract

The phase diagrams of two nanoscaled thin films with bond and site dilutions at the surfaces, described by the spin-1 transverse Ising model, are investigated by the use of an effective field theory with correlations. A number of characteristic phenomena have been found in them, which are heavily dependent on the ratios (r = J1/J and p = ΩS/Ω, where J is the exchange interaction in the inner layer, J1 is the exchange interaction between the surface and the next inner layer, ΩS is the transverse field at the surfaces and Ω is the transverse field in the inner layer). Some of them have exhibited very similar behaviors found in the two spin-1/2 nanoscaled thin films with bond and site dilutions at the surfaces.

DOI
10.1080/01411594.2013.789105

Related papers

The effects of bulk and surface fields on the phase diagram of a transverse Ising thin film

T. Kaneyoshi

Abstract The phase diagram of a transverse Ising thin film is investigated by the use of two theoretical frameworks, namely the standard mean field theory and the effective field theory. The effects of the ratio p between the bulk and surface transverse fields on the critical temperature are discussed by including the modification of surface exchange interaction. Some characteristic features are found in the phase diagrams when the ratio p increases from p = 1.0. They are enhanced for the film with thickness L smaller than 5.0. In particular, the critical ratio at which the critical temperature of the film with a finite transverse field reduces to zero, being independent of L, exhibits a linear relation when it is plotted against the modification of surface exchange interaction.

physica status solidi (b)•Apr 16, 2003•22 citations

Phase Diagrams of the Semi-Infinite Spin-1/2 Ising Model and Spin-1/2 Ising Film in a Random Transverse Surface Field

B. Laaboudi, M. Saber, M. Kerouad

The critical behavior of both semi-infinite spin-1/2 Ising system and spin-1/2 Ising film in a random transverse surface field has been studied within an effective field theory. The effect of the ratio R of the surface exchange interaction to the bulk one, random transverse surface field and film thickness on the phase diagrams are investigated.

physica status solidi (b)•Mar 1, 1999•7 citations

The effect of the surface field on the phase diagrams of a transverse Ising thin film

H. Arhchoui, Y. El Amraoui

Within an effective field theory (EFT), the phase diagrams of a transverse Ising thin film (TIM) has been investigated. The effects of the Ωs on the critical temperature are discussed by including the modification of surface exchange interaction. The phase diagrams are also determinated as function of the transverse field for different values of the film thickness n and for same value of ∆s

PRSM•Mar 14, 2011•0 citations

Phase Diagrams of the Site-Diluted Spin-i Ising Film in a Transverse Field

A. Saber, A. Ainane, F. Dujardin +2 more

Within the framework of the effective field theory, with a probability distribution technique that accounts for the single-site spin correlations, we examine the critical behavior of a diluted spin-1/2 Ising film. The critical temperature of the system is studied as a function of the thickness of the film, the concentration of magnetic atoms, the strength of the transverse field and the couplings. It is shown that for the ratio of the surface couplings to the bulk ones R = Js/J less than a critical value R,, the critical temperature of the film Tc/J is smaller than the bulk critical temperature Tc^B/J and for R ≥ Rc, Tc/J is larger than the bulk critical temperature Tc^B/J and Tc^S/J of the corresponding semi-infinite system. As the film thickness L is increased further Tc/J increases for R ≤ Rc (decreases for R 2 R,) and approaches asymptotically for large values of L the bulk critical temperature Tc^B/J (the surface critical temperature Tc^S/J) of the corresponding semi-infinite system.

Chinese Journal of Physics•Apr 1, 1999•0 citations

Phase diagrams of diluted ferromagnetic Ising films in a transverse field

J. C. Cressoni, J.W. Tucker, Enaldo F. Sarmento

An effective-field theory that accounts for the self-spin correlation function is used to study the effect of surface dilution on the critical behavior of a ferromagnetic Ising film in transverse surface and bulk fields. Surface exchange enhancement (or reduction) is considered. It is shown that the surface and bulk fields affect the critical ratio of surface to bulk interactions, at which the surface orders before the bulk, in opposite ways. Although it is found that for the undiluted film this leads to a critical ratio that is practically insensitive to field for common bulk and surface field strengths, this feature is relaxed to a certain degree with surface dilution. The thickness dependence of the critical temperature, and phase diagrams in the fields, interaction strength ratio, and dilution parameter space, are presented.

Journal of Applied Physics•May 15, 1994•5 citations

Transverse Ising Model with Diluted Surface and Modified Surface-Bulk Coupling

T. Lahcini, Noureddine Benayad

The transverse Ising system with a diluted surface and a modified surface-bulk interaction J(subscript ┴) is studied by the use of an effective field method within the framework of a single-site cluster theory. The surface antiferromagnetic exchange interaction JS is distributed randomly and has a concentration p. The new parameter p strongly affects the phase diagram obtained in the pure case (p=1). Indeed, some qualitatively interesting features have been found, both in the absence and in the presence of the surface transverse field. In particular, we defined a critical value p(superscript *) of p, separating two qualitatively different behaviors of the system.

Chinese Journal of Physics•Apr 1, 2009•0 citations
The phase diagrams of two nanoscaled thin films with bond and site dilutions at the surfaces, described by the spin-1 transverse Ising model, are investigated by the use of an effective field theory with correlations. A number of characteristic phenomena have been found in them, which are heavily dependent on the ratios (r = J1/J and p = ΩS/Ω, where J is the exchange interaction in the inner layer, J1 is the exchange interaction between the surface and the next inner layer, ΩS is the transverse field at the surfaces and Ω is the transverse field in the inner layer). Some of them have exhibited very similar behaviors found in the two spin-1/2 nanoscaled thin films with bond and site dilutions at the surfaces.
Abstract The phase diagram of a transverse Ising thin film is investigated by the use of two theoretical frameworks, namely the standard mean field theory and the effective field theory. The effects of the ratio p between the bulk and surface transverse fields on the critical temperature are discussed by including the modification of surface exchange interaction. Some characteristic features are found in the phase diagrams when the ratio p increases from p = 1.0. They are enhanced for the film with thickness L smaller than 5.0. In particular, the critical ratio at which the critical temperature of the film with a finite transverse field reduces to zero, being independent of L, exhibits a linear relation when it is plotted against the modification of surface exchange interaction.
Within the framework of the effective field theory, with a probability distribution technique that accounts for the single-site spin correlations, we examine the critical behavior of a diluted spin-1/2 Ising film. The critical temperature of the system is studied as a function of the thickness of the film, the concentration of magnetic atoms, the strength of the transverse field and the couplings. It is shown that for the ratio of the surface couplings to the bulk ones R = Js/J less than a critical value R,, the critical temperature of the film Tc/J is smaller than the bulk critical temperature Tc^B/J and for R ≥ Rc, Tc/J is larger than the bulk critical temperature Tc^B/J and Tc^S/J of the corresponding semi-infinite system. As the film thickness L is increased further Tc/J increases for R ≤ Rc (decreases for R 2 R,) and approaches asymptotically for large values of L the bulk critical temperature Tc^B/J (the surface critical temperature Tc^S/J) of the corresponding semi-infinite system.
An effective-field theory that accounts for the self-spin correlation function is used to study the effect of surface dilution on the critical behavior of a ferromagnetic Ising film in transverse surface and bulk fields. Surface exchange enhancement (or reduction) is considered. It is shown that the surface and bulk fields affect the critical ratio of surface to bulk interactions, at which the surface orders before the bulk, in opposite ways. Although it is found that for the undiluted film this leads to a critical ratio that is practically insensitive to field for common bulk and surface field strengths, this feature is relaxed to a certain degree with surface dilution. The thickness dependence of the critical temperature, and phase diagrams in the fields, interaction strength ratio, and dilution parameter space, are presented.
The transverse Ising system with a diluted surface and a modified surface-bulk interaction J(subscript ┴) is studied by the use of an effective field method within the framework of a single-site cluster theory. The surface antiferromagnetic exchange interaction JS is distributed randomly and has a concentration p. The new parameter p strongly affects the phase diagram obtained in the pure case (p=1). Indeed, some qualitatively interesting features have been found, both in the absence and in the presence of the surface transverse field. In particular, we defined a critical value p(superscript *) of p, separating two qualitatively different behaviors of the system.