Brillouin scattering from rapidly quenched ferromagnetic metallic glasses

Abstract

We report on Brillouin-scattering measurements of thermally excited surface acoustic phonons, and bulk and surface magnons, in quenched ribbons of ferromagnetic metallic glasses with compositions Fe100−xBx (x=14–28), Fe76Mo4B20, FexNi80−xB20 (x=20–60), and Co75−xFexSi15B10 (x=0–6). Room-temperature surface-phonon velocity is found to increase monotonically with increasing B in FeB, and with increasing Fe in FeNiB. The velocity is almost 10% less in Fe76Mo4B20 than in Fe80B20. The phonon velocity is not field dependent, even in compositions where large ΔE effects occur. The g factor, determined from the slope of surface-magnon frequency with field, is 2.09±0.02 for Fe100−xBx. The intensity of surface- and bulk-magnon scattering is independent of magnetostriction in CoFeSiB.