An integral equation approach to orientational phase transitions in two and three dimensional disordered systems
The use of inhomogeneous Ornstein-Zernike equations to analyze phase transitions and ordered phases in magnetic systems is explored both in bulk three dimensional disordered Heisenberg systems and in a simple model for a two dimensional ferrofluid monolayer. In addition to closures like the Mean...
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| Дата: | 2001 |
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| Автори: | , , |
| Формат: | Стаття |
| Мова: | English |
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Інститут фізики конденсованих систем НАН України
2001
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| Назва видання: | Condensed Matter Physics |
| Онлайн доступ: | http://dspace.nbuv.gov.ua/handle/123456789/119758 |
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| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | An integral equation approach to orientational phase transitions in two and three dimensional disordered systems / E. Lomba, F. Lado, J.J. Weis // Condensed Matter Physics. — 2001. — Т. 4, № 1(25). — С. 45-66. — Бібліогр.: 34 назв. — англ. |
Репозитарії
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irk-123456789-1197582017-06-09T03:04:48Z An integral equation approach to orientational phase transitions in two and three dimensional disordered systems Lomba, E. Lado, F. Weis, J.J. The use of inhomogeneous Ornstein-Zernike equations to analyze phase transitions and ordered phases in magnetic systems is explored both in bulk three dimensional disordered Heisenberg systems and in a simple model for a two dimensional ferrofluid monolayer. In addition to closures like the Mean Spherical Approximation, Hypernetted Chain and Zerah-Hansen approximation, the inhomogeneous Ornstein-Zernike equation must be complemented by a one-body closure, for which the Born-Green equation has been used in this paper. The results obtained prove that the proposed approach can furnish accurate estimates for the paramagneticferromagnetic transition in the three dimensional Heisenberg spin fluid, reproducing reliably the structure of the isotropic and ordered phases. In two dimensions, the results are fairly accurate as well, both for the dipolar film alone and in the presence of external perpendicular fields. At high densities/dipole moments the equation seems to predict a transition to a phase in which the dipoles lie mostly in the plane and are aligned into vortex-like structures. Evidence of this new phase is found in the simulation at somewhat higher couplings Використання неоднорідних рівнянь Орнштейна-Церніке для вивчення фазових переходів і впорядкованих фаз в магнітних системах досліджується як у невпорядкованих гайзенбергівських системах так і в простій моделі для двовимірного ферофлюїдного моношару. Неоднорідне рівняння Орнштейна-Церніке, крім таких замикань як середньосферичне, гіперланцюгове і наближення Зера-Гансена, мусить бути доповнене одно-частинковим замиканням, для якого було використано в цій статті рівняння Борна-Гріна. Отримані результати доводять, що запропонований підхід може давати точні оцінки для переходу парамагнетик-феромагнетик в тривимірному гайзенбергівському спіновому флюїді, надійно відтворюючи структуру ізотропної і впорядкованої фаз. У двох вимірах, результати є, безумовно, точними як для дипольної плівки без поля, так і в присутності зовнішніх перпендикулярно направлених полів. При високих густинах/дипольних моментах рівняння передбачають перехід до фази, в якій диполі лежать в основному в площині і утворюють вихороподібні структури. Наявність цієї нової фази є знайдена при дещо сильніших параметрах при моделюванні. 2001 Article An integral equation approach to orientational phase transitions in two and three dimensional disordered systems / E. Lomba, F. Lado, J.J. Weis // Condensed Matter Physics. — 2001. — Т. 4, № 1(25). — С. 45-66. — Бібліогр.: 34 назв. — англ. 1607-324X PACS: 61.20.Gy, 68.15.+e, 75.10.-b, 75.30.-m DOI:10.5488/CMP.4.1.45 http://dspace.nbuv.gov.ua/handle/123456789/119758 en Condensed Matter Physics Інститут фізики конденсованих систем НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| language |
English |
| description |
The use of inhomogeneous Ornstein-Zernike equations to analyze phase
transitions and ordered phases in magnetic systems is explored both in
bulk three dimensional disordered Heisenberg systems and in a simple
model for a two dimensional ferrofluid monolayer. In addition to closures like
the Mean Spherical Approximation, Hypernetted Chain and Zerah-Hansen
approximation, the inhomogeneous Ornstein-Zernike equation must be
complemented by a one-body closure, for which the Born-Green equation
has been used in this paper. The results obtained prove that the
proposed approach can furnish accurate estimates for the paramagneticferromagnetic
transition in the three dimensional Heisenberg spin fluid, reproducing
reliably the structure of the isotropic and ordered phases. In two
dimensions, the results are fairly accurate as well, both for the dipolar film
alone and in the presence of external perpendicular fields. At high densities/dipole
moments the equation seems to predict a transition to a phase
in which the dipoles lie mostly in the plane and are aligned into vortex-like
structures. Evidence of this new phase is found in the simulation at somewhat
higher couplings |
| format |
Article |
| author |
Lomba, E. Lado, F. Weis, J.J. |
| spellingShingle |
Lomba, E. Lado, F. Weis, J.J. An integral equation approach to orientational phase transitions in two and three dimensional disordered systems Condensed Matter Physics |
| author_facet |
Lomba, E. Lado, F. Weis, J.J. |
| author_sort |
Lomba, E. |
| title |
An integral equation approach to orientational phase transitions in two and three dimensional disordered systems |
| title_short |
An integral equation approach to orientational phase transitions in two and three dimensional disordered systems |
| title_full |
An integral equation approach to orientational phase transitions in two and three dimensional disordered systems |
| title_fullStr |
An integral equation approach to orientational phase transitions in two and three dimensional disordered systems |
| title_full_unstemmed |
An integral equation approach to orientational phase transitions in two and three dimensional disordered systems |
| title_sort |
integral equation approach to orientational phase transitions in two and three dimensional disordered systems |
| publisher |
Інститут фізики конденсованих систем НАН України |
| publishDate |
2001 |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/119758 |
| citation_txt |
An integral equation approach to orientational phase transitions in two and three dimensional disordered systems / E. Lomba, F. Lado, J.J. Weis // Condensed Matter Physics. — 2001. — Т. 4, № 1(25). — С. 45-66. — Бібліогр.: 34 назв. — англ. |
| series |
Condensed Matter Physics |
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