Brillouin scattering from bismuth substituted yttrium iron garnet single crystals

Magnon spectra of bismuth substituted yttrium iron garnet (Bi
x
Y
3-x
Fe
5
O
12
, X=0,0.14,0.36,0.54,0.90) were measured by means of the Brillouin light scattering technique. According to the measured dispersion relation of the thermal excited bulk magnon, we deduced the magnetic parameters (D.γ. 4πMs) It is found that both the spin wave stiffness constant D and the light scattering crosssection of the bulk magnon are enhanced by increased substitution of bismuth.