Low-temperature thermophysical properties of Fe₃Si

Abstract

Measurements of the thermal expansion of Fe₃Si in the temperature range 2-300 K are reported. The low-temperature linear thermal expansion of Fe₃Si is accurately described by the expression α = (-3·5±0·5)x 10⁻⁹ T + (47middot;07plusmn;2) × 10⁻¹² T ³ K⁻¹, being the sum of a linear electronic contribution and a cubic lattice contribution. The thermal expansion is negative below 24 K. The failure to find evidence for low-temperature T ^3/2 spin-wave contributions to the low-temperature thermophysical properties of Fe₃Si is shown to be consistent with the very low values for the spin-wave thermophysical coefficients predicted on the basis of neutron-scattering experiments. Values for the electronic and lattice Grüneisen parameters in the low-temperature limit are calculated. The negative electronic Grüneisen parameter for Fe₃Si is shown to be consistent with band-structure calculations which all predict a large peak in the electronic density of states at the Fermi surface.