Study Of Spin Waves In Ferromagnetic Bilaters With Bcc Structure

On the basis of the Heisenberg exchange model, the spin-wave eigen-problem of the ferromagnetic bilayers with body centered cubic structure was solved exactly at the low temperature. First of all, the spin-wave energy bands of the bilayers composed of same ferromagnetic films were presented and compared with the Puszkarski's study. Furthermore, in the bilayers composed of different ferromagnetic films, the influences of the transverse (parallel to the film plane) spin-waves on the property of quantized longitudinal (vertical to the film plane) spin-waves were extensively studied. A detailed description on all kinds of waveforms of the vertical spin waves, spin-wave energy bands and dispersion relations were presented. And all of these results were compared with the previous work that was devoted to the case of the simple cubic structure. Many important conclusions were drawn: 1) the waveform and the energy of the quantized longitudinal spin-wave mode were different in the body centered cubic crystal structure; 2) the transverse spin-waves were also influenced, and thus the type and energy of the quantized longitudinal spin-waves in the volume of the bilayers were changed prominently; 3) The interface exchange constant J_AB also influence the type and amount of the spin-wave modes; 4) For the increasing magnetic field, not only the energy of the eigen modes increase linearly, but also the modes transformd from one to another.