Pressure Effect on the Spontaneous Volume Magnetostriction of Fe-Ni and Fe-Pt Invar Alloys

Pressure effect on the spontaneous volume magnetostriction ω s of Fe-Ni and Fe-Pt Invar alloys is studied by measuring the pressure dependence of lattice constants usins X-rav diffraction technique. The pressure derivative of ω s and the magnetic contribution to the compressibility in Fe-Ni Invar alloy near 0 K are found to be largely different from those in Fe-Pt Invar alloy. The differences are interpreted phenomenologically in terms of the pressure dependence of T c and M 0 and suggested to relate with the stability of magnetic moment at low temperature.