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

Detalhes bibliográficos
Autor(a) principal: Mendoza Coto, Alejandro
Data de Publicação: 2016
Outros Autores: Billoni, Orlando Vito, Cannas, Sergio A., Stariolo, Daniel Adrian
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Repositório Institucional da UFRGS
Texto Completo: http://hdl.handle.net/10183/158511
Resumo: We introduce a coarse-grained model capable of describing the phase behavior of two-dimensional ferromagnetic systems with competing exchange and dipolar interactions, as well as an external magnetic field. An improved expression for the mean-field entropic contribution allows us to compute the phase diagram in the whole temperature versus external field plane. We find that the topology of the phase diagram may be qualitatively different depending on the ratio between the strength of the competing interactions. In the regime relevant for ultrathin ferromagnetic films with perpendicular anisotropy we confirm the presence of inverse-symmetry breaking from a modulated phase to a homogeneous one as the temperature is lowered at constant magnetic field, as reported in experiments. For other values of the competing interactions we show that reentrance may be absent. Comparing thermodynamic quantities in both cases, as well as the evolution of magnetization profiles in the modulated phases, we conclude that the reentrant behavior is a consequence of the suppression of domain wall degrees of freedom at low temperatures at constant fields.
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spelling Mendoza Coto, AlejandroBilloni, Orlando VitoCannas, Sergio A.Stariolo, Daniel Adrian2017-05-25T02:27:30Z20160163-1829http://hdl.handle.net/10183/158511001009917We introduce a coarse-grained model capable of describing the phase behavior of two-dimensional ferromagnetic systems with competing exchange and dipolar interactions, as well as an external magnetic field. An improved expression for the mean-field entropic contribution allows us to compute the phase diagram in the whole temperature versus external field plane. We find that the topology of the phase diagram may be qualitatively different depending on the ratio between the strength of the competing interactions. In the regime relevant for ultrathin ferromagnetic films with perpendicular anisotropy we confirm the presence of inverse-symmetry breaking from a modulated phase to a homogeneous one as the temperature is lowered at constant magnetic field, as reported in experiments. For other values of the competing interactions we show that reentrance may be absent. Comparing thermodynamic quantities in both cases, as well as the evolution of magnetization profiles in the modulated phases, we conclude that the reentrant behavior is a consequence of the suppression of domain wall degrees of freedom at low temperatures at constant fields.application/pdfengPhysical review. New York. Vol. 94, no. 5 (Aug. 2016), 054404,8 p.Diagramas de faseFilmes finos magneticosTransições magnéticasQuebra de simetriaAnisotropia magnética perpendicularCampos magnéticosModulated systems in external fields : conditions for the presence of reentrant phase diagramsEstrangeiroinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFRGSinstname:Universidade Federal do Rio Grande do Sul (UFRGS)instacron:UFRGSORIGINAL001009917.pdf001009917.pdfTexto completo (inglês)application/pdf1846080http://www.lume.ufrgs.br/bitstream/10183/158511/1/001009917.pdf389b82855b64b19103b1e30fd6f7a3eaMD51TEXT001009917.pdf.txt001009917.pdf.txtExtracted Texttext/plain36089http://www.lume.ufrgs.br/bitstream/10183/158511/2/001009917.pdf.txt7a3a12c9797c1b8f28f6e8a963452273MD5210183/1585112017-08-17 02:36:04.985529oai:www.lume.ufrgs.br:10183/158511Repositório de PublicaçõesPUBhttps://lume.ufrgs.br/oai/requestopendoar:2017-08-17T05:36:04Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)false
dc.title.pt_BR.fl_str_mv Modulated systems in external fields : conditions for the presence of reentrant phase diagrams
title Modulated systems in external fields : conditions for the presence of reentrant phase diagrams
spellingShingle Modulated systems in external fields : conditions for the presence of reentrant phase diagrams
Mendoza Coto, Alejandro
Diagramas de fase
Filmes finos magneticos
Transições magnéticas
Quebra de simetria
Anisotropia magnética perpendicular
Campos magnéticos
title_short Modulated systems in external fields : conditions for the presence of reentrant phase diagrams
title_full Modulated systems in external fields : conditions for the presence of reentrant phase diagrams
title_fullStr Modulated systems in external fields : conditions for the presence of reentrant phase diagrams
title_full_unstemmed Modulated systems in external fields : conditions for the presence of reentrant phase diagrams
title_sort Modulated systems in external fields : conditions for the presence of reentrant phase diagrams
author Mendoza Coto, Alejandro
author_facet Mendoza Coto, Alejandro
Billoni, Orlando Vito
Cannas, Sergio A.
Stariolo, Daniel Adrian
author_role author
author2 Billoni, Orlando Vito
Cannas, Sergio A.
Stariolo, Daniel Adrian
author2_role author
author
author
dc.contributor.author.fl_str_mv Mendoza Coto, Alejandro
Billoni, Orlando Vito
Cannas, Sergio A.
Stariolo, Daniel Adrian
dc.subject.por.fl_str_mv Diagramas de fase
Filmes finos magneticos
Transições magnéticas
Quebra de simetria
Anisotropia magnética perpendicular
Campos magnéticos
topic Diagramas de fase
Filmes finos magneticos
Transições magnéticas
Quebra de simetria
Anisotropia magnética perpendicular
Campos magnéticos
description We introduce a coarse-grained model capable of describing the phase behavior of two-dimensional ferromagnetic systems with competing exchange and dipolar interactions, as well as an external magnetic field. An improved expression for the mean-field entropic contribution allows us to compute the phase diagram in the whole temperature versus external field plane. We find that the topology of the phase diagram may be qualitatively different depending on the ratio between the strength of the competing interactions. In the regime relevant for ultrathin ferromagnetic films with perpendicular anisotropy we confirm the presence of inverse-symmetry breaking from a modulated phase to a homogeneous one as the temperature is lowered at constant magnetic field, as reported in experiments. For other values of the competing interactions we show that reentrance may be absent. Comparing thermodynamic quantities in both cases, as well as the evolution of magnetization profiles in the modulated phases, we conclude that the reentrant behavior is a consequence of the suppression of domain wall degrees of freedom at low temperatures at constant fields.
publishDate 2016
dc.date.issued.fl_str_mv 2016
dc.date.accessioned.fl_str_mv 2017-05-25T02:27:30Z
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dc.identifier.uri.fl_str_mv http://hdl.handle.net/10183/158511
dc.identifier.issn.pt_BR.fl_str_mv 0163-1829
dc.identifier.nrb.pt_BR.fl_str_mv 001009917
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dc.language.iso.fl_str_mv eng
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dc.relation.ispartof.pt_BR.fl_str_mv Physical review. New York. Vol. 94, no. 5 (Aug. 2016), 054404,8 p.
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