Lattice Dynamics in Ferromagnetic Invar Alloys, Fe₃Pt and Fe₆₅Ni₃₅

抄録

The phonon dispersion relations in ferromagnetic Invar alloys, Fe₃Pt and Fe₆₅Ni₃₅, have been measured along the high-symmetry directions. The temperature as well as wave number (q) dependence of the phonon frequency shift, the linewidth in [110] TA₁ mode, have been observed. The results of these observations characterize the Invar problems. The relatively weak forces between nearest neighbor Fe atoms are responsible for the appearance of the soft mode in fcc Fe Invar alloys, according to the force constant analyses of the observed dispersion curves.