Magnetic Compton Scattering Studies of the Invar Effect in Fe3Pt

Abstract

AbstractWe have measured the magnetic Compton profile (MCP) of ordered and disordered Fe 3Pt samples both above and below their Curie temperature. From these measurements, we have determined the average moment per atom at room temperature to be 2.81μB ± 0.04μB for disordered Fe3Pt and 1.78μB ± 0.05μB for ordered Fe3Pt. At temperatures above Tc, we measured a substantial reduction in the moment (0.6μB ± 0.10μB for disordered Fe3Pt and 0.64μB ± 0.13μB ± for ordered Fe3Pt) and a change in the shape of the MCP. This suggests that the mechanism behind the Invar effect in Fe3Pt can be described by a high-spin to low-spin magnetic phase transition. The experimental MCPs for both ordered and disordered Fe3 Pt are analyzed within the framework of the Weiss 2γ model.