Properties of the magnon populations in the super lattice [Fe/GaAs]

The purpose of this work is to study the properties of elementary excitations in a magnetic super lattice [Fe/GaAs]. The study is obtained in framework of the ferromagnetic Heisenberg system where the exchange and the dipolar interactions, the magneto-crystalline and surface anisotropies are all taking into account. The corresponding Hamiltonian is treated by the Greenʹs function method. The analytical expressions of the excitation spectrum and the magnetization per spin are obtained when the exchange is present alone. A good adjustment of calculated magnetization with the experimental results is obtained for various magnetic layer thickness (tFe). The deduced exchange integrals are in agreement with previous studies. The combined effect of dipolar interactions and surface anisotropy is studied numerically.