A New Low Temperature Phase (fct) of Fe–Pd Invar

Abstract

A new fct phase of disordered Fe–Pd Invar alloys was found at low temperatures. The low temperature phase diagram was obtained from X-ray diffraction experiments (4.2 K to 300 K). The fct phase ranges from 28% to 33.5% Pd at 0 K and the temperature dependence of lattice constants was determined. A decrease of the X-ray Debye temperature associated with a lattice softening was observed for 34% Pd in the low temperature region.