Spin-1 Model of Noninteracting Nanoparticles |
| O. Yalçin a, R. Erdem b and S. Övűnç c
a Department of Physics, Bozok University, 66500, Yozgat, Turkey b Department of Physics, Gaziosmanpasa University, 60250, Tokat, Turkey c Decosel, Keresteciler Sitesi 12, Block No. 1, Ikitelli-Istanbul, Turkey |
| Full Text PDF |
| Received: 24 12 2007; Revised version: 6 06 2008; |
| In this work, we presented a spin-1 model to investigate the magnetic properties of noninteracting monodomain nanoparticles based on the pair approximation. Nearest-neighbor pair interactions are incorporated between the Ising spins in three parts that are core, core-surface, and surface within the nanoparticle. Using the spin-1 Ising model of magnetization in the pair approximation, we calculated the free energy and minimized with respect to pair variables to obtain the field-cooled magnetization. Hysteresis loops of the system were plotted for various values of exchange coupling constants, and axial anisotropy of strength which couples the core, core-surface, and surface regions. The coercive field and its linear fit to the data were plotted as a function of radius of ferromagnetic nanoparticles. |
| DOI: 10.12693/APhysPolA.114.835 PACS numbers: 75.50.Tt, 75.60.-d, 05.50.+q, 05.70.Ln |