Two-dimensional Heisenberg Ferromagnetic System Research Articles

Realization of an excellent two-dimensional Heisenberg ferromagnetic system: the synthesis, structure, and thermodynamic properties of piperazinediium tetrabromocuprate

A 2D Heisenberg ferromagnet with ultra-small interlayer coupling realized in a metal–organic crystal.

Magnon–phonon coupling in two-dimensional Heisenberg ferromagnetic system

A magnon–phonon interaction model is set up for a two-dimensional insulating ferromagnetic system. By using Matsubara function theory, we have studied the magnon spectrum and calculated the magnon dispersion curve on the main symmetric point and line in the Brillouin zone for various parameters of the system. The results show that at the boundary of Brillouin zone, there is a strong magnon softening. The contributions of longitudinal and transverse phonons on the magnon softening are compared and the influences of various parameters are also discussed.

Phonon damping in two-dimensional Heisenberg ferromagnetic system at finite temperature

A magnon-phonon interaction model is developed on the basis of two-dimensional square Heisenberg ferromagnetic system. The transverse acoustic phonon damping and longitudinal acoustic phonon damping are studied through Matsubara Green function theory, and transverse acoustic phonon damping and longitudinal acoustic phonon damping curves are calculated on the main symmetric point and line in the first Brillouin zone. It’s found that in the first Brillouin zone, on line Δ, there is no damping for the transverse acoustic phonon, on line Z, there is no damping for longitudinal acoustic phonon. In the first Brillouin zone, the transverse acoustic phonon damping is one order larger than the longitudinal acoustic phonon damping. The influences of transverse acoustic phonon damping and longitudinal acoustic phonon damping for different parameters on them are also illustrated in this article. According to the relationship between phonon damping and phonon lifetime, and the relationship between phonon damping and phonon density of state, the lifetime and density of state for transverse acoustic phonon and longitudinal acoustic phonon is discussed.

Effect of magnon–phonon interaction on phonon damping of two-dimensional Heisenberg ferromagnetic system at finite temperature

A magnon–phonon interaction model is developed on the basis of a two-dimensional square Heisenberg ferromagnetic system. By using Matsubara Green function theory we studied the transverse and longitudinal acoustic phonon dampings and calculated the transverse and longitudinal acoustic phonon damping curves on the main symmetric point and line in the first Brillouin zone. It is found that on the line Δ there is no damping for transverse acoustic phonon and on the line Z there is no damping for longitudinal acoustic phonon. In the first Brillouin zone the damping of transverse acoustic phonons is at least one order larger than that of longitudinal acoustic phonons. The influences of various parameters on transverse and longitudinal acoustic phonon dampings are discussed and the lifetime and the density of state of transverse and longitudinal acoustic phonons are explored as well according to the relation of the phonon damping and its lifetime and the relation of the phonon damping and its density of state.

Magnon damping in two-dimensional Heisenberg ferromagnetic system

A magnon–phonon interaction model is set up for a two-dimensional insulating ferromagnetic system. By using Matsubara function theory we have studied the magnon damping − I m Σ ∗ ( 1 ) ( k → ) and calculated the magnon damping − I m Σ ∗ ( 1 ) ( k → ) curve on the main symmetric point and line in the Brillouin zone for various parameters in the system. It is concluded that at the boundary of Brillouin zone there is a strong magnon damping. However, the magnon damping is very weak on the zone of small wave vector and the magnon damping reaches maximal value at very low temperature. The contributions of longitudinal phonon and transverse phonon on the magnon damping are compared and the influences of various parameters are also discussed.

Effect of optical phonon on magnetic excitation of two-dimensional Heisenberg ferromagnetic system

A magnon-phonon interaction model is built in the two-dimensional double square ferromagnetic system. By using Matsubara Green function theory, we study magnetic excitation of the system, and calculate the magnon dispersion curve on the main symmetric points and lines in the Brillouin zone. The influences of optical phonon and acoustic phonon on the magnetic excitation of the system are compared, and the influences of the parameter change on the magnon softening are also studied. It is concluded that the coupling of the optical phonon and magnon has predominant effect on the magnon softening, especially the longitudinal optical phonon has the greatest effect on the magnon softening, and the effect of nonmagnetic ion on magnon softening is stronger than that of magnetic ion.