SOFTENING OF PHONON DENSITY-OF-STATES IN FE-BASED AMORPHOUS INVAR-ALLOYS

Inelastic neutron-scattering experiments and thermal expansion measure ments on amorphous Fe90-xCoxZr10 (x = 10 and 40) and Fe80-yCrP13C7 (y = 4 and 8) alloys have been performed. Generalized phonon densities of states (PDOS) were deduced from the measured time-of-flight spectra a t room temperature. The results show that the generalized PDOS in the energy region below 17 meV become soft at the Invar concentrations for both amorphous Fe90-xCoxZr10 and Fe80-yCryP13C7 alloys. It is suggest ed that the softening of the low energy PDOS in Fe-based amorphous Inv ar alloys could be attributed to the enhancement of electron-phonon in teraction.