مرکز منطقه ای اطلاع رساني علوم و فناوري - The effect of ellipticity on the direction of spinwave rays

Abstract :

Parallel pumping high signal power microwave radiation is a powerful tool to detect spinwave instabilities, since it allows to infer intrinsic damping properties of ferrimagnets. Several experiments of the last years have shown that the spinwave linewidth $\\Delta H_{k}$ does not always follow the $(H_{c}-H_{i})^{1/2}$ law for π/2 magnon scattering. This feature is attributed to the existence of a non zero $\\underline {z}$ -component of the spinwave propagation vector $\\underline {k}$ . Simple formulas, derived from the dispersion relation are presented in this paper, which evidence the dependence on the spinwave ellipticity $\\varepsilon (\\vartheta _{k})$ of the propagation characteristics of the excited magnons. Also, in the case of three boson processes, the influence of ε on $\\Delta H_{k}(H_{i})$ is briefly discussed in the light of the spinwave transit-time theory.