Magnetism of Invar alloys under pressure examined by inelastic x-ray scattering

The magnetic properties of the Invar alloy Fe64Ni36 have been investigated by x-ray emission spectroscopy as a function of pressure up to 20 GPa. With increasing pressure, the amplitude of the Fe local moment, deduced from the Fe K beta line satellite intensity, is reduced at two characteristic step values. This pressure dependence is interpreted in terms of transitions from a high-spin state to a low-spin state at approximate to5 GPa followed by a transition to a nonmagnetic state above 15 GPa. This behavior provides a microscopic picture of the Fe magnetism in agreement with the 2 gamma -state model.