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Investigation of size effects on the physical properties of one-dimensional ising models in nanosystems

Taherkhani, F ; Sharif University of Technology | 2011

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  1. Type of Document: Article
  2. DOI: 10.1080/00268976.2010.524172
  3. Publisher: 2011
  4. Abstract:
  5. Ising models in nanosystems are studied in the presence of a magnetic field. For a one-dimensional (1-D) array of spins interacting via nearest-neighbour and next-nearest-neighbour interactions we calculate the heat capacity, the surface energy, the finite-size free energy and the bulk free energy per site. The heat capacity versus temperature exhibits a common wide peak for systems of any size. A small peak also appears at lower temperatures for small arrays when the ratio of magnetic field spin interaction energy over the nearest-neighbour spin-spin interaction energy, f, is within 0 < F ≤ 0.10 . The peak becomes smaller for longer array and eventually vanishes for long arrays, disappearing when the number of spins, N, is greater than 25 when only nearest-neighbour interactions are taken into account, and more than 14 when next-nearest-neighbour interactions are included as well. Ising models in which the nearest-neighbour interactions are ferromagnetic, while the next-nearest-neighbour interactions are either ferromagnetic or antiferromagnetic, are compared, and it is found that the reduced free energy in the former case exhibits a larger deviation from the bulk value
  6. Keywords:
  7. Heat capacity ; Antiferromagnetics ; Bulk free energy ; Bulk value ; Heat capacities ; Nearest-neighbour ; Nearest-neighbour interactions ; Next-nearest-neighbour interaction ; One-dimensional Ising model ; Size effect ; Size effects ; Spin interaction ; Spin-spin interaction ; Surface energies ; Surface energy ; Antiferromagnetism ; Ferromagnetic materials ; Ferromagnetism ; Free energy ; Interfacial energy ; Ising model ; Magnetic fields ; Models ; Size determination ; Specific heat ; Surface chemistry ; Nanosystems
  8. Source: Molecular Physics ; Volume 109, Issue 3 , Feb , 2011 , Pages 385-395 ; 00268976 (ISSN)
  9. URL: http://www.tandfonline.com/doi/abs/10.1080/00268976.2010.524172