Magnon and acoustic-phonon light scattering from Bi-doped yttrium iron garnet.

Abstract

Light scattering in Bi-substituted yttrium iron garnet has revealed different excitation-wavelength-dependent cross sections for the acoustic phonons and magnons. Analysis of the magnon and phonon frequencies showed a quadratic and linear dependence, respectively, with wave vector and models for these results indicate that the spin-wave stiffness constant is increased, while the sound velocity is reduced, by the substitution of Y with Bi. With the reduction of excitation wavelength, which is accompanied by an increase in the light absorption, a line broadening, and finally a double peak with a continuous band in between, is observed in magnon scattering.