Modulated systems in external fields: Conditions for the presence of reentrant phase diagrams

Mendoza-Coto, Alejandro; Billoni, Orlando V.; Cannas, Sergio A.; Stariolo, Daniel A.

doi:10.1103/physrevb.94.054404

Cited by 10 publications

(10 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In an attempt to explain this experimental observations, a scaling theory was developed to relate the presence of a certain family of microscopic interactions with the existence of reentrant behavior in the phase diagram 26 . More recently, the same reentrant behavior have been found within mean-field approximations for systems with dipolar repulsive interactions in the context of Landau-Ginzburg models 27 , lattice models 28 and others 29 . Many of these efforts focus on the relation between the IM behavior with an entropy gain from domain wall degrees of freedom of the modulated patterns.…”

Section: Introductionsupporting

confidence: 66%

“…The minimization technique we perform in this work is analogous to that used in Ref. 29 . We are interested in solutions that minimize the effective free energy.…”

Section: Minimization Of the Effective Hamiltoniansmentioning

confidence: 99%

“…Additionally, the values of the critical fields as a function of the reduced temperature are very close. Considering that the strict mean field approach has been used more often in previous works 29,32 , in what follows the overall presented analysis have been obtained within this approximation.…”

Section: Namementioning

confidence: 99%

See 2 more Smart Citations

On the mechanism behind the inverse melting in systems with competing interactions

Mendoza-Coto

Nicolao

Díaz-Méndez

2019

Sci Rep

Self Cite

View full text Add to dashboard Cite

The competition between a short range attractive interaction and a nonlocal repulsive interaction promote the appearance of modulated phases. In this work we present the microscopic mechanisms leading to the emergence of inverse transitions in such systems by considering a thorough mean-field analysis of a variety of minimal models with different competing interactions. We identify the specific connections between the characteristic energy of the homogeneous and modulated phases and the observed reentrant behaviors in the phase diagram. In particular, we find that reentrance is appreciable when the characteristic energy cost of the homogeneous and modulated phases are comparable to each other, and for systems in which the local order parameter is limited. In the asymptotic limit of high energy cost of the homogeneous phase we observe that the degree of reentrance decreases exponentially with the ratio of the characteristic energy cost of homogeneous and modulated phases. These mean-field results are confronted with Langevin simulations of an effective coarse grained model, confirming the expected extension of the reentrance in the phase diagram. These results shed new light on many systems undergoing inverse melting transitions by qualitatively improving the understanding of the interplay of entropy and energy around the inverse melting points.

show abstract

Section: Introductionsupporting

confidence: 66%

“…The minimization technique we perform in this work is analogous to that used in Ref. 29 . We are interested in solutions that minimize the effective free energy.…”

Section: Minimization Of the Effective Hamiltoniansmentioning

confidence: 99%

See 1 more Smart Citation

On the mechanism behind the inverse melting in systems with competing interactions

Mendoza-Coto

Nicolao

Díaz-Méndez

2019

Sci Rep

Self Cite

View full text Add to dashboard Cite

show abstract

“…The experimental results presented in the next subsections refer to a ferromagnetic model system representative of the Hamiltonian (1) with α =3 (refs 18, 19, 27, 33, 34, 35, 36). Some unconventional behaviours observed in these ferromagnetic films, such as the systematic occurrence of inverse-symmetry-breaking transitions of magnetic-domain patterns, have been explained theoretically starting from the Hamiltonian (1)2837. In the limit of J ≫ g , relevant for the experimental system, the spectrum of the elastic-like excitations mentioned above is gapless.…”

Section: Resultsmentioning

confidence: 99%

Critical exponents and scaling invariance in the absence of a critical point

et al. 2016

View full text Add to dashboard Cite

The paramagnetic-to-ferromagnetic phase transition is classified as a critical phenomenon due to the power-law behaviour shown by thermodynamic observables when the Curie point is approached. Here we report the observation of such a behaviour over extraordinarily many decades of suitable scaling variables in ultrathin Fe films, for certain ranges of temperature T and applied field B. This despite the fact that the underlying critical point is practically unreachable because protected by a phase with a modulated domain structure, induced by the dipole–dipole interaction. The modulated structure has a well-defined spatial period and is realized in a portion of the (T, B) plane that extends above the putative critical temperature, where thermodynamic quantities do not display any singularity. Our results imply that scaling behaviour of macroscopic observables is compatible with an avoided critical point.

show abstract

“…Following standard procedures the mean field free energy of the system in the continuum limit is given by 26,29…”

Section: Modelmentioning

confidence: 99%

Topological phase diagrams of the frustrated Ising ferromagnet

Mendoza-Coto,

de Oliveira,

Nicolao

et al. 2019

Preprint

Self Cite

View full text Add to dashboard Cite

The emergence of complex modulated structures in the magnetization pattern of thin films is a wellestablished experimental phenomenology caused by the frustrating effects of competing interactions. Using a coarse-grained version of the Ising ferromagnet with dipolar interactions, we develop a method that use the information from the microscopic Hamiltonian to predict the specific topology of these phases. This is done with a combination of the mean-field phase diagrams obtained by minimization of the free energy functional, and the classical theory of melting. In this frame we are able to clearly distinguish orientational and translational symmetry and discriminate between the long and short range ordering of the system for all temperatures and fields. We observe that the reentrance developed by the H-T phase diagrams in the regime of weak dipolar interactions is directly related with the appearance of anomalous topological transitions. These results motivate the realization of new experiments on magnetic thin films allowing to determine the connection between the reentrance and the behavior of the topological phases in real materials.

show abstract

Modulated systems in external fields: Conditions for the presence of reentrant phase diagrams

Cited by 10 publications

References 25 publications

On the mechanism behind the inverse melting in systems with competing interactions

On the mechanism behind the inverse melting in systems with competing interactions

Critical exponents and scaling invariance in the absence of a critical point

Topological phase diagrams of the frustrated Ising ferromagnet

Contact Info

Product

Resources

About