آنتی فرومغناطیس

Strong and long-range coupling of the magnetization dynamics of the two antiferromagnetic layers mediated by the phonons transferred through a nonmagnetic insulator has been investigated. The magnetization dynamics in one of the antiferromagnetic layers via a magnetoelastic interaction leads to the excitation of phonons and their pumping to the nonmagnetic layer. The transfer of phonons, which carry angular momentum, through a nonmagnetic insulator from one antiferromagnetic layer to another, leads to an interference pattern in the absorption spectrum, which represents the coupling of magnetization dynamics of two layers.

Entanglement is one of the fundamental quantum concepts that not only distinguishes quantum mechanics from its classical counterpart but also plays important roles in quantum communication and information processing technologies. Here, we aim to study anisotropy contributions of continuous variable entanglement between magnon modes in antiferromagnets. By introducing different bosonic modes, it is shown that the magnetic uniaxial anisotropy induces different entanglement contributions in the ground state of the system. While some of these contributions appear to be decreasing with respect to anisotropy, the other contributions are increasing as functions of anisotropy. It is also shown that the maximum magnon entanglement is always at the centre of Brillouin zone. The analysis presented here is independent of geometric lattice structure and appropriate for many classes of compounds.

In this paper, the formulation of spin coherent state in the real parameter in SU(1,1) group is studied. This representation of the coherent state is used for measuring the integral path and its classical consequence in the physical system. Using the completeness relation of the coherent state, we derive a path integral expression for transition amplitude and in the classical limit, we solve the classical equation of motion. Then, Lagrangian, equations and dispersion relation describing one-dimensional exchange anisotropic Non-Heisenberg model in the Anti-ferromagnetic system for dipole branch are calculated.