Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8161613 | Physica B: Condensed Matter | 2018 | 6 Pages |
Abstract
In this paper we have studied the stabilization of the long-range order in (z;x)-plane of two isotropic Heisenberg ferromagnetic monolayers coupled by a short-range exchange interaction (Jâ¥), by a long range dipole-dipole interactions and a magnetic field. We have applied a magnetic field along of the z-direction to study the thermodynamic properties above the critical temperature. The dispersion relation Ï and the magnetization are given as function of dipolar anisotropy parameter defined as Ed=(gμ)2S/a3J⥠and for other Hamiltonian parameters, and they are calculated by the double-time Zubarev-Tyablikov Green's functions in the random-phase approximation (RPA). The results show that the system is unstable for values of Edâ¥0.012 with external magnetic field ranging between H/Jâ¥=0 and 10â3. The instability appears for Ed larger then Edc=0.0158 with H/Jâ¥=10â5, Edc=0.02885 with H/Jâ¥=10â4, and Edc=0.115 with H/Jâ¥=10â3, i.e., a small magnetic field is sufficient to maintain the magnetic order in a greater range of the dipolar interaction.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
R.M.V. de Souza, T.A.S. Pereira, M. Godoy, A.S. de Arruda,