Anisotropy effects on the magnetic excitations of a ferromagnetic monolayer below and above the Curie temperature

dc.creatorPini, M. G.
dc.creatorPoliti, P.
dc.creatorStamps, R. L.
dc.date2005-03-22
dc.date2005-07-22
dc.date.accessioned2026-07-07T03:04:16Z
dc.date.available2026-07-07T03:04:16Z
dc.descriptionThe field-driven reorientation transition of an anisotropic ferromagnetic monolayer is studied within the context of a finite-temperature Green's function theory. The equilibrium state and the field dependence of the magnon energy gap $E_0$ are calculated for static magnetic field $H$ applied in plane along an easy or a hard axis. In the latter case, the in-plane reorientation of the magnetization is shown to be continuous at T=0, in agreement with free spin wave theory, and discontinuous at finite temperature $T>0$, in contrast with the prediction of mean field theory. The discontinuity in the orientation angle creates a jump in the magnon energy gap, and it is the reason why, for $T>0$, the energy does not go to zero at the reorientation field. Above the Curie temperature $T_C$, the magnon energy gap $E_0(H)$ vanishes for H=0 both in the easy and in the hard case. As $H$ is increased, the gap is found to increase almost linearly with $H$, but with different slopes depending on the field orientation. In particular, the slope is smaller when $H$ is along the hard axis. Such a magnetic anisotropy of the spin-wave energies is shown to persist well above $T_C$ ($T \approx 1.2 T_C$).
dc.descriptionFinal version accepted for publication in Physical Review B (with three figures)
dc.identifierhttps://arxiv.org/abs/cond-mat/0503538
dc.identifierhttp://arxiv.org/abs/cond-mat/0503538
dc.identifierPhys. Rev. B 72, 014454 (2005) (11 journal pages)
dc.identifierdoi:10.1103/PhysRevB.72.014454
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/26071
dc.subjectMaterials Science
dc.titleAnisotropy effects on the magnetic excitations of a ferromagnetic monolayer below and above the Curie temperature
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